{"id":"001065444","type":"book","title":"Circular fortresses in the provinces of North and South Holland (West Frisia)","publisher":"Wachholtz","publisher-place":"Neumünster","pages":"201-218","container-title":"Ringwälle und verwandte Strukturen des ersten Jahrtausends n. Chr. Internationales Symposium. Utersum auf Föhr 29. September - 1. Oktober 2005","author":[{"family":"Dijkstra","given":"Menno"}],"issued":{"raw":"2009"}}