Szpak, P., Gröcke, D., Debruyne, R., MacPhee, R., Guthrie, R., Froese, D., …Poinar, H. (2010). Regional differences in bone collagen δ13C and δ15N of Pleistocene mammoths: Implications for paleoecology of the mammoth steppe. Palaeogeography, Palaeoclimatology, Palaeoecology, 286(1-2), 88-96. https://doi.org/10.1016/j.palaeo.2009.12.009