References

Pals, J.-P. 1999, Preliminary notes on crop plants & natural/anthropogenous vegetation. In: J.C. Besteman, J.M. Bos, D.A. Gerrets, H.A. Heidinga & J. de Koning (eds), The excavations at Wijnaldum. Reports on Frisia in Roman and Medieval times, Rotterdam (Balkema), 139-149.