M.J. van der Meulen, W.E. Westerhoff, A. Menkovic, S.H.L.L. Gruijters, C.W. Dubelaar and D. Maljers (2009) “Silica sand resources in the Netherlands”, Netherlands Journal of Geosciences, 88, pp. 147 - 160. doi: 10.1017/S001677460000086X.