Horton , T. W., J. D. Blum, Z. Xie, M. Hren, and C. P. Chamberlain. “Stable Isotope Food-Web Analysis and Mercury Biomagnification in Polar Bears (Ursus Maritimus)”. Polar Research, vol. 28, no. 3, Dec. 2009, pp. 443-54, doi:10.3402/polar.v28i3.6135.