This is your DIY manual for enlarging or creating your own terp – your artificial settlement mound or house platform to be protected against sea or river floods, depending on where they were built. Despite terps having been erected on the tidal marshlands of the Wadden Sea for more than 2,600 years, this manual is the first of its kind. We sincerely hope it’s not too little, too late now that terp-building is on the rise again, and we’ve observed that this often happens in an amateurish way, with unnecessary safety risks being taken.
Although most terps were built in the period between 650 BC and AD 1050, it's still a current solution. Take, for example, the terp constructed next to the town of Wieringerwerf, located in the embanked land of Wieringermeerpolder in the province of Noord Holland. The town and terp were founded in the '30s of the last century. The terp was even of service at the end of the Second World War when the dikes of the Wieringermeerpolder were destroyed. Read our post Refuge on a terp 2.0, waiting to be liberated, about this catastrophe. The most recent terps were built ten years ago in the region Overdiepse Polder in the province of Noord Brabant. It's part of the Delta Plan after serious flooding caused by the big rivers Rhine and Meuse two decades ago. Lastly, at the time of writing, folks from the village of Blije in the province of Friesland have a cunning plan to build a terp too.
However, it deeply troubled the Nordfriesen and the Ostfriesen in Germany, and the Frisians in the province of Friesland in the Netherlands, that the residents of the province of Noord-Brabant, and the province of Noord-Holland already before, do not obey all necessary rituals and procedures. In time, this might have very serious consequences for the safety and health of the people who dwell on these terps. Therefore, the Frisian bastards felt it was urgent to produce a manual to avoid future, similar irresponsible behaviour.
Be warned that children should construct ramps only under the direct supervision of an adult. Adults should read the instructions, and in particular, all warnings, carefully. Of course, we're not responsible for any injuries or accidents.
Let’s start. Be prepared, it's literally a lot of bullshit!
A: Location
If you want to know where in the landscape erecting a terp is opportune, check the site www.overstroomik.nl (translation: will I be submerged?) provided by the Netherlands' government. Really, this site and its title are not meant to scare people, but to show them where their house would be submerged in case a dyke breaks, and how to be prepared. These are the spots where this manual comes in handy. The website is only available in Dutch, and thus not accessible for expats living in the Netherlands. At the time of writing, the number of expats is between 40,000 and 75,000 persons and they mostly live in the low-lying coastal zone of the provinces Noord-Holland and Zuid-Holland. Who is counting?
B: Materials
eight (or more) skulls of ancestors
ten kilogram cattle meat with bones
one heirloom piece
three cooking pans (not too small)
drill
ten kilogram pottery
hammer
eight hundred cubic meter cow dung (depending on your ambitions)
shovel
stack of firewood
box fire matches
sea shells (enough to cover the terp surface)
C: Instructions
Best time to erect a terp is in early summer. You don't want to work with dung in the heavy spring, autumn, and winter rains. Also, for the containers to drain (see step 7 below) would take ages. Last but not least, making fires (see steps 8 and 9 below) in these rains is nearly impossible.
Place your ancestral skulls at the spot where you want the terp to be erected, or an existing terp enlarged. WARNING!: Do not hurry off to kill some of your (close) family members. No! You need to collect remains of your already deceased family members. The terp is to protect you and your family, and the remains will call upon your ancestors for extra protection. Instead, there are many Grave Registration Services on the internet that can help you to locate graves of your ancestors. Some traditions recommend to add a dog skull. This manual considers it optional, as this practice of dog skulls is more related to the maintenance of a house and not that of a terp.
Place the meat with bones near the human skulls. Make a little pile of it. The traditional way was that several cows were slaughtered for the occasion. You can go to a local butcher but spare ribs from the supermarket will suffice too. Argentinian matured T-bone steaks are unnecessary expensive, and don't give a better result. Of course, we stimulate to use biological products. An option of last resort is to use jelly sweets, since they consist partly of cattle bone. As a rule of thumb: ten kilogram jelly sweet for every kilogram of meat.
Place the heirloom piece near the skulls too. Taking a piece from your in-laws is acceptable as long as it has serious sentimental value for your in-law family. Up to you whether or not you ask permission from your loved in-laws.
Now the hard work starts. It feels like Herakles cleaning the Augean stable. Dump the cow dung with the shovel gently over the skulls and over all the other items. There's no alternative but to use predominantly cow dung, since it has a great insulating effect. No human dung, please. Sorry, keep using toilets. WARNING!: Neither horse dung, since it's highly infectious. Blending with sheep dung is not such a problem. Where it comes down to, is that you need loads and loads of dung. In this respect not much has changed over the last 2,600 years: cow dung has always been plentiful at the salt marshes. In the old days used for fuel and, of course, for building terps. Later, after the big dikes emerged 1,000 years ago, and the sea was banned, dung was suddenly needed as fertilizer. And, its insulating effects are now a threat for the climate.
Dig ditches around the terp. About a meter wide, but not much broader. For a man of average weight and strength, it must be possible to fierljep ('to far-leap') over the ditch with a four-meter-long leaping pole. The ditches have multiple purposes. Firstly, they are for draining purposes. Secondly, they mark your territory. Thirdly, they have a spiritual meaning, namely fencing of the inner world form the outer (scary) world. Check the Indiculus superstitionum et paganiarum, the eighth-century list of heathen practices of the Frisians and the Saxons.
Wait until dusk.
At dusk, take the cooking pans and drill a small hole in the bottom. Similar as the Mayas later did too with the pottery they buried with the dead. The traditional way of the Frisians was to grab used cooking pots of clay. Essence is that you need containers. Then and now. So, modern pans are perfectly okay to use. Mark the pans from the outside with some of your own blood. No specific patterns prescribed. Fill the pans with a sticky substance that slowly drips through the hole into the dung. Place these containers on the spot above the skulls, meat and heirloom piece.
Make a few small piles of wood and light the piles. Again, above the spot where the skulls are buried. WARNING!: Make sure the cow dung isn't too dry, to prevent the whole terp from catching fire. Dried dung is flammable. And we're not in Nordfriesland in February during the yearly biikin celebrations.
Wait until the liquid in the cooking pans has fully been drained into the dung. You'll have enough time to have dinner in the meantime. Important to keep the fires burning.
Collect the pottery once the liquid is drained. It can be all sorts of pottery. If you're tired of the Delft Blue wall tiles; use those. But roof tiles, your neighbor's china etc., is fine too. Smash the pottery with a hammer and bury it together with the empty perforated cooking pans in a pit somewhere in the newly created terp. Smash or deform the pans too. Frisians were fanatics in breaking pottery and collected meaningful pieces for decades. If you think this is weird, think of a Greek wedding.
Dump some of the pottery pieces in the ditches surrounding your terp too. If you have some spare bones of your ancestors left, put it there together with the pottery pieces. It stresses the mark of your territory like a dog pisses against a tree. And the water in the ditches protects your house or inner-world against the spiritual, angry outer-world as well.
Lastly, cover the surface of the new terp with a thick layer of sea shells to have a solid and less smelling floor.
Have a safe and pleasant stay on your terp!
The ritual practices of this Manual have been confirmed by archaeologists; Nieuwhof, A., Eight human skulls in a dung heap and more. Ritual practice in the terp region of northern Netherlands 600 BC-AD 300 (2015).
ANNEX
Between Leffinge-Oude Werf (BE) and Misthusum (DK):
Understanding Terps
definition & varieties
First of all, we must make clear that the terps we dealt with in this manual, are terps built on the clay soils of the (former) salt marshes.
A terp, in essence, is a man-made raised mound to dwell on and to protect buildings, livestock and food stocks from inundation. Whether that's on the tidal marshlands bordering the sea, on the peatlands adjacent to those marshlands, or along rivers and at river mouths. Exactly the habitats of wider historic Frisia. Terps can be a mound to support a single house, often called a platform, or a mound to support a small settlement of a few hundred people.
Therefore, besides terps built on salt marshes or 'salt-water terps', this definition also includes the hundreds of terps found in the peatlands of the modern province of Noord Holland, especially in the region of Waterland, and also the town-terps of settlements like Monnickendam and Amsterdam. These so-called 'sweet-water terps', in connection with rivers and peatlands, existed in the thousands in the Netherlands (Besteman et al 1992).
‘Sweet-water terps’ at the (former) peatlands were mainly house platforms. Furthermore, the terps at the peatlands all have become invisible for the eye. The reason for it is that peat behaves like water. It flows too, only in slow motion. Over centuries it levels with its surroundings. Terps made of clay and dung on the tidal marshlands, however, remained visible much longer, albeit clay too behaves like water at the end.
Besides sweet-water terps in peatlands, there are many hundreds of sweet-water terps in the river area of the Central Netherlands. This is especially the region of Batavia, or in the Dutch language, the region of Betuwe. This area only became embanked with dykes from around the year 1000 onward. Toponyms like pol, heuvel, hof, werf and woerd might refer to these (former) artificial mounds, either to dwell on or for refuge during river floodings. The latter toponym woerd might also refer to an elevated acre. Of all the terps about 580 are dwelling mounds of which the majority on riverbanks, and elevated with clay and sods (Eijgenraam et al 2022).
To complicate things further, the distinction between saltwater and sweet water was in practice fluid, especially in much of the peat areas. Either you are a delta or you are not.
Terps on Kampereiland 'Kampen island' in the delta of the River IJssel belong to this fluid category as well, until the Zuiderzee 'southern sea' was sealed off in the '30s of the twentieth century and slowly turned into the sweet-water Lake IJsselmeer. Kampereiland's rich soil is a mixture of sea and river clay. In the year 1364, the town of Kampen received the rights over fourteen islands in the delta which later would compose Kampereiland. The earliest mention of the terps on Kampereiland dates from the fifteenth century, the moment when the islands are being inhabited (Nijlunsing 2016, Molema 2018). A terp on Kampereiland is locally known as a huisbelt 'house heap/dump' or a pol 'clump', and on average 2 à 3 meters above mean sea level (MOD). The oldest terps can be found on the river banks (Eilander & Heijink 1990). There are about a hundred farmyards on Kampereiland, most of which are built on a huisbelt (Molema 2018). Find them, for example, along Frieseweg ‘Frisian road’. But also visit the local history museum 'Ons Erf' where a farmstead in its original state, including barns and haystack, can be visited.
Salt-water terps can be found in relatively large numbers especially along the Wadden Sea coastal zone of Denmark, Flanders, Germany and the Netherlands. The oldest terps can be found in the territory of Westergo in the province of Friesland. From there terps spread eastward into northern Germany. The northernmost terp is that of Misthusum in the southwest of the region of Jutland in Denmark. It regrettably has been abandoned in the year 1814. The southernmost terp on the North Sea coast is at Leffinge in the region of Flanders in Belgium (see further below).
Because people lived on terps on tidal marshlands before high dykes existed, the North Sea could flow out over a vast area of marshland during storm floods. Terps were on average not much higher than +4 MOD (compare Kampereiland). Higher was simply not necessary and thus not worth the effort. The sea just flowed out during storms without, in general, causing too much damage because of this enormous storage capacity.
Highest terp of all is the one at the hamlet of Hogebeintum, namely almost +9 MOD. Why the people of Hogebeintum built such a high terp in the Middle Ages when +4 meters was already enough, we don't know. Was it perhaps to show off? “Look us having a big terp!” Like driving a Porche Panamera. Or was it for religious reasons? Or were the villagers very anxious and traumatized people? Or did they simply have too much spare time to kill? Other famous terps are those of Feddersen in Landkreis Cuxhaven and of Ezinge in the province of Groningen. The latter is also nicknamed ‘Pompeii of the North’ because of the magnificent archaeological excavations before the Second World War (Nieuwhof 2020).
Other ‘salt-water terps’ can be found elsewhere too, i.e. not along the Wadden Sea coast. For example more to the south in the region of Westfriesland in the province of Noord Holland there are two clusters with each about thirty terps (Borger 2021). One cluster is in and around the town of Schagen, like the terps of Avendorp, Eenigenburg and Hemkewerf. The other cluster of terps is located around the villages of Eenigenburg and Warmenhuizen. Further south, in the province of Zuid Holland on island Hoeksche Waard more terps can be found near the village of Strijen.
And even further south, in the region of Flanders in Belgium, you can find terps at the villages of Leffinge, Bredene, and Oude Werf near Leffinge. Terp Oude Werf being the southernmost terp of the North Sea coast as well. Other terps the Zwin area in the region of Flanders are being suspected at Knokke, Koudekerke, Oostkerke, Ramskapelle and Westkapelle. Also, toponyms Lockwierde, Houtwerf, Outvaarts Werf, Bogaerts Werf, Zuidwerf, Stekels Werf, Boenzacs Werf, Blevins Werf, Barezeles Werf, Molenwerf, Monnikewerve, Wallewerve, Weerdenwal, and many many more, all might refer to (former) presence of terps. Much archaeological research still has to be done in the region of Flanders, including the Zwin area. Check also our post The Frontier known as Watery Mess: the coast of Flanders to find more information about the early-medieval Flemish-Frisian terp habitation in the region of Flanders.
Also, on the (former) islands of Marken and Schokland at the (former) Zuiderzee ‘southern sea’ you can find in total fifteen of the once twenty-seven terps, locally known as werven. For example Wittewerf, Kerkbuurt, Remmitswerf, Kets, Moeniswerf, Grotewerf, Altena and Rozewerf. But also the drowned terps Kraaienwerf, Thamiswerf and Houtemanswerf. Three terps lost to the sea between 1720 and 1775 (Aarsen et al 2000, Rijkswaterstaat 2024). Island Marken still is, more or less, a Hallig-island, whilst Schokland is now part of the embanked land called Noordoostpolder. Even underneath the marine town of Den Helder in the upper north of the province of Noord Holland, lies an old salt-water terp waiting for its revanche. It's named Het Torp 'the village'. Actually, it's the terp of former settlement of Edesthorpa. Located near natural park and museum De Nollen, where once a small island was, and near current neighbourhood De Schooten.
Recently (2019), federation Broekpolder reconstructed the so-called Rottahuis 'Rotta house' (viz. the River Rotta) with a platform of the year 1015 at the town of Vlaardingen in the province of Zuid Holland, then still called West Frisia. It illustrates how people lived in the river delta of the River Meuse. Go visit it, now part of the interesting experimental archaeological site Masamuda.
living entity & memory
Some more words concerning the distinction between a terp supporting several houses and/or farms (village), and a terp supporting solely one farm or one house. The latter may not even be called a terp according to tradition. As a Frisian farmer living on a house platform near the village Sexbierum in the province of Friesland explained once to one of the Frisian bastards, and not without emotion:
“It is a platform, not a terp!”
Never ever contradict a Frisian farmer.
But more subtle, you could hear a kind of sacred-like respect for terps in his voice. It was simply an insult to compare a terp with a house platform. As if a terp is a living thing. Bit the same saying to a North-Frisian that a Hallig (see below) is an island. He will correct you in a grumpy voice, and say it's not an island. Then he will probably say "moin" to you and walk -or swim- away, depending on the tide. He's right in the way that Hallig-islands used to be part of a vast salt marsh area, which largely was lost to the sea in the course of the High Middle Ages. Too fresh in the memory in the psyche of the Nordfriesen to be forgotten, if ever. Admitting it's an island, would be admitting your defeat against your eternal enemy, and benefactor, which took so much fertile land, livestock and especially so many lives.
statistics & money
When talking about numbers, the estimation is that about 500 terps existed in the (former) tidal marshlands of the province of Friesland (Besteman et al 1992). House platforms have been left outside this number. Numbers vary too. During a stock-take, including house platforms, in 1905 the number of terps amounted 574 in the province of Friesland, and in 1944 the number amounted 910. The most recent (2020) numbers are that in the province of Friesland 955 terps have been identified of which 679 have been partially or completely levelled, and in the province of Groningen 587 of which 268 have been partially or completely levelled. However, still new terps are being discovered in the landscape. The total original number of salt-water terps in the north of the Netherlands, both terps proper and house platforms, is estimated almost 2,500 (Nieuwhof 2020).
Therefore, if we want to be more precise, we should talk about ‘terp remains’ instead of terps since nearly all terps have been commercially exploited, excavated and levelled. The terps you can still see in the provinces of Friesland and Groningen, are mostly the remains of once much more impressive terps, or those which are fully covered with houses, farmsteads and a church, and therefore escaped commercial exploitation.
Around the year 1900, terps in the northern Netherlands, less in the region of Ostfriesland in Germany, were being excavated massively for commercial purposes. The rich terp soil, the terra preta of the Low Countries, was sold as fertilization for poorer soils, such as the sandy soils in the province of Drenthe. Terp soil was sold at 70 cent (guilders) per tonne in 1890, which was a lot of money back then. In 1920, terp soil even cost 110 cents per tonne. In the ’40s, commercial quarrying of terp soil stopped. Not because of the Second World War started. No, because not many terps were left to be commercially exploited. A positive side effect was that because of these excavations many artifacts have been found. At the same time, much historical (provenance) data has been lost, and small artifacts are scattered all over the country, depending on where the terp soil was dispersed as fertilizer.
Although most salt-water terps have lost their protective function after land had been secured by big-dyke building from around the start of the eleventh century, there's one big exception, namely those in Landkreis Nordfriesland in Germany. Here, one can still witness people living on terps within the full dynamics of the sea, unprotected by high dykes. These are the so-called Hallig-islands mentioned earlier, which are salt marsh islands with one or a few terps on it. Terps, sometimes supporting only one farm or house, sometimes supporting a small village. For more information about the Hallig-islands, read also our post How a town drowned overnight. Currently (2021), after a thousand years, the terps on the Hallig-islands of Nordfriesland are being raised once again. To brace themselves for climate change, global warming and rising sea levels.
belt, terp, værft, wierde, Warf, werf, Wurt, etc.
Notice that we used the word terp as used in the province of Friesland -and recently in the province of Noord Brabant too. People in the province of Noord Holland, however, mostly use the word werf. In the province of Zeeland and the region of Flanders the word werve is being used, although the toponym wi(e)rde or weerde and stelle also exist. The word werve in the province of Zeeland mainly because people there prefer to put the letter e behind every single word they pronounce. In the province of Groningen the word wierde is always being used. Official German is Wurt but the Ostfriesen and Nordfriesen use mainly respectively Warf and Warft. Frisere ‘Frisians’ in the very southwest of the region of Jutland in Denmark use the words værft or varft.
The Old-Frisian word hwarf and the current word werf, and all the variants aforementioned, indicate a mound or a landing. Werf and Warft would, therefore, be more appropriate terms for a dwelling mound than the internationally adopted word terp. Don't tell this to the Frisians in the province of Friesland. The word terp is related to the word torp (Danish language), doarp (Mid-Frisian language) or dorp (Dutch language). However, it's terp that found its way into the English and Flemish languages, and therefore we settle the discussion this way. Majority always rules.
For a full overview of all the nearly thirty (30!) different names that exist for a terp, check the atlas 'De Bosatlas van de Wadden' (2018). They failed to list one or two in this list. One mentioned above, namely huisbelt in the delta of the River IJssel. But also vliedberg 'flee mountain', as (also) being used in the region of Flanders and the province of Zeeland. The word vliedberg can donate a mound for cattle the flee to during floods, it can be a remnant of motte-and-bailey castle, or a terp proper.
Note 1 - On behalf of all the Frisians we do apologize for the global heating effects of our dung culture.
Note 2 - Two more terps have been built in the Netherlands recently, and both in the municipality of The Hague. Both as monuments, and not meant for a settlement platform. These are the Terp of Vink, and the terp at the town of Leidschenveen. Read our post Terp or wierde? Even more exotic, in '30s of the twentieth century, the dairy farm Friesche Terp was set up in Pengalengan near the city of Bandung in the Dutch-Indies, present-day Indonesia.
Note 3 - In the province of Friesland, the inhabitants of terp village Blije set up the project Terp van de Toekomst 'terp of the future' and want to build a terp at the tidal marshland again, north of the village Blije. It would be the first terp build on the salt marsh after more than a thousand years.
Note 4 - You can be giggly about the practice of digging ditches and marking your territory with pottery and bones of your ancestors, but it's actually the foundation of modern Western society. Ditches, banks, walls, hedges and so on, embodied control over resources through agricultural property rights. They gave among others expression to social relationships, status and communal identity. Yes, identity originally was determined by the land the group possessed and not by genes and origin (Oosthuizen 2019).
Suggested music
Reboelje, Eilân yn de see (1999)
The Cult, She Sells Sanctuary (1985)
Further reading
Aarsen, A., Dingemans, M. & Kooiman, M.A., Cultuurhistorische verkenningen. Marken (2000)
Bank, J. & Bosscher, D., Omringd door water. De geschiedenis van de 25 Nederlandse eilanden (2021)
Besteman, J.C., Bos, J.M. & Heidinga, H.A., Graven naar Friese koningen. De opgravingen in Wijnaldum (1992)
Betten, E., Terpen- en wierdenland (2018)
Borger, G.J., De Zijpe en de Zuiderzee (2021)
Deckers, P., Ervynck, A. & Tys, D., De vroegmiddeleeuwse bewoning van de kustvlakte: de terp site Leffinge-Oude Werf (2012)
Dijkstra, M.F.P, Rondom de mondingen van Rijn en Maas. Landschap en bewoning tussen de 3de en 9de eeuw in Zuid-Holland, in het bijzonder de Oude Rijnstreek (2011);
Doorn, van F., De Friezen. Een geschiedenis (2021)
Eijgenraam, G., Beek, van R. & Candel, J., Hoog en droog naast de rivier. De archeologische rijkdom van woonheuvels in de Betuwe (2022)
Eilander, D.A. & Heijink, W., Bodemkaart van Nederland. Toelichting bij de kaartbladen 20 West Lelystad (gedeeltelijk), 20 Oost Lelystad en 21 West Zwolle (1990)
Ervynck, A., Deckers, P., Lentacker, A., Tys, D. & Neer, van M., ‘Leffinge-Oude Werf’: the first archaeozoological collection from a terp settlement in coastal Flanders (2012)
Everdingen, van J., Droogte maakt contouren van middeleeuws terpdorp bij Strijen zichtbaar: ‘Dit is van groot belang’ (2022)
Frankfurt, H.G., On Bullshit (1986)
Halbertsma, H., Terpen tussen Vlie en Eems. Een geografisch-historische benadering (1963)
Hofstede, J., Küstenschutz in Schleswig-Holstein: ein Überblick über Strategien und Maßnahmen (2019)
Knol, E., Friese terpen doorgesneden (2023)
Knol, E., Hogebeintum aan snee (2019)
Knol, E., et al, The medieval cemetery of Oosterbeintum (Friesland) (1996)
Maijer, M., IJsseldelta bij Kampen (2021)
Mann, C.C., 1491. New Revelations of the Americas Before Columbus (2006)
Meier, D., Ausgrabung: Hundorf (website)
Meier, D., Die Halligen. In Vergangenheit und Gegenwart (2020)
Molema, M.M.L., Buurmans gras is altijd groener. Een interdisciplinair onderzoek naar de landschapskenmerken, bezitsverhoudingen en gebruiksgeschiedenis van hooilanden in de IJsseldelta tijdens de 19e en 20e eeuw (2018)
Nicolay, J. & Langen, de G. (eds.), Graven aan de voet van de Achlumer dorpsterp (2015)
Nicolay, J. & Langen, de G. (eds.), Friese terpen in doorsnede. Landschap, bewoning en exploitatie. Deel I: het onderzoek in woord en beeld (2023)
Nicolay, J. & Langen, de G. (eds.), Friese terpen in doorsnede. Landschap, bewoning en exploitatie. Deel II: profiel- en vlaktekeningen (2023)
Nieuwhof, A., 650 Terpen langs de Noordzee (2018)
Nieuwhof, A., Eight human skulls in a dung heap and more. Ritual practice in the terp region of northern Netherlands 600 BC-AD 300 (2015)
Nieuwhof, A., De lege vierde eeuw (2016)
Nieuwhof, A., Ezinge Revisited. The Ancient Roots of a Terp Settlement. Volume 1: Excavation – Environment and Economy – Catalogue of Plans and Finds (2020)
Nieuwhof, A., Scherven brengen geluk. Aanwijzingen voor opzettelijk gebroken aardewerk (2018)
Nieuwhof, A., Bakker, M., Knol, E., Langen, de G.J., Nicolay, J.A.W., Postma, D., Schepers, M., Varwijk, T.W., Vos, P.C., Adapting to the sea: Human habitation in the coastal area of the northern Netherlands before medieval dike building (2019)
Nijlunsing, W., Kamper munten in muntvondst Kampen 2010 (2016)
Oosthuizen, S., The emergence of the English (2019)
Pleijster, E.J., Veeken, van der C. & Jongerius, R., Dijken van Nederland (2014)
Popta, van Y. & Aaldersberg, G., Onbekend, maar niet onbemind: terpen en terponderzoek in de Noordoostpolder (2016)
Remkes, J., Wat wel kan: uit de impasse en een aanzet voor perspectief (2022)
Renswoude, van O., De Huigen en het Humsterland (2022)
Renswoude, van O., Leeuwarden en andere warden (2022)
Rijkswaterstaat, Dijkversterking Marken: archeologische vondst (2024)
Roessingh, W., Een archeologische opgraving op ‘Het Torp’ (2018)
Versloot, A., De herbewoning van de Friese kwelders en terpnamen. Een onderzoek naar mogelijke verbanden (2021)
Westerink, B., Wierdenlandschap (2022)
Wiersma, J.P. (ed.), Bruorren Halbertsma, Rimen en teltsjes; De Terp (1969)
Zwaenepoel, A. & Vandamme, D., Herders, schapen en natuurbeheer in de Zwinstreek (2016)