P.J. Felder, E. Keppens, B. Declercq, S. Normand and M. Streel (2003) “Faunal/floral and isotopic responses to Milankovitch precession cycles and environmental changes in the upper Gulpen Formation (Upper Maastrichtian) at the CBR-Lixhe and ENCI-Maastricht bv quarries”, Netherlands Journal of Geosciences, 82, pp. 275-281. doi: 10.1017/S0016774600020862.