H. Bocherens and D. Drucker, «Dietary Competition between Neanderthals and Modern Humans: Insights from Stable Isotopes,» in When Neanderthals and Modern Humans Met, ed. N. Conard (Tubingen: Kerns Verlag, 2006), 129–143; Germonpre et al., «Possible Evidence of Mammoth Hunting»; P. Semal, H. Rougier, I. Crevecoeur et al., «New Data on the Late Neandertals: Direct Dating of the Belgian Spy Fossils,» American Journal of Physical Anthropology 138 (2009): 421–428.