O.S. Knottnerus, 'Reclamations and submerged lands in the Ems River Estuary, 1900-1500'. In: Erik THoen et al. (eds.), Landscapes or seascapes?. The history of the coastal environment in the North Sea area reconsidered, Turnhout 2013, S. 241-266.
Frank Westerman: De graanrepubliek. Atlas, Amsterdam/Antwerpen 1999, erweitert 2009. [Deutsche Ausgabe Das Getreideparadies. Ch. Links, Berlin 2009, ISBN 978-3-86153-550-8.]