Isotopic Values of Antarctic Krill in Relation to Foraging Habitat of Penguins Kokubun, Nobuo and Choy, Eun-Jung and Kim, Jeong-Hoon and Takahashi, Akinori, Ornithological Science, 14, 13-20 (2015), DOI:http://dx.doi.org/10.2326/osj.14.13