References
Bult, E.J. & D.P. Hallewas 1990, Archaeological evidence for the early-medieval settlement around the Meuse and Rhine deltas up to ca AD 1000. In: J.C. Besteman, J.M. Bos & H.A. Heidinga (eds), Medieval archaeology in the Netherlands. Studies presented to H.H. van Regteren Altena, Assen/Maastricht, 71-90.