Horton , T. W., Blum , J. D., Xie , Z., Hren , M. and Chamberlain , C. P. (2009) “Stable isotope food-web analysis and mercury biomagnification in polar bears (Ursus maritimus)”, Polar Research, 28(3), pp. 443-454. doi: 10.3402/polar.v28i3.6135.