Richards, M. P., Pacher, M., Stiller, M., Quilès, J., Hofreiter, M., Constantin, S., . . . Trinkaus, E. (2008). Isotopic evidence for omnivory among European cave bears: Late Pleistocene Ursus spelaeus from the Peştera cu Oase, Romania. National Academy of Sciences.

Richards, Michael P., Martina Pacher, Mathias Stiller, Jérôme Quilès, Michael Hofreiter, Silviu Constantin, João Zilhão, and Erik Trinkaus. Isotopic Evidence for Omnivory Among European Cave Bears: Late Pleistocene Ursus Spelaeus From the Peştera Cu Oase, Romania. National Academy of Sciences, 2008.

Richards, Michael P., et al. Isotopic Evidence for Omnivory Among European Cave Bears: Late Pleistocene Ursus Spelaeus From the Peştera Cu Oase, Romania. National Academy of Sciences, 2008.