Ballance, L. T., Ainley, D. G., Ballard, G., & Barton, K.. (2009).
An energetic correlate between colony size and foraging effort in seabirds, an example of the Adélie penguin Pygoscelis adeliae.
Journal of Avian Biology,
40(3), 279 - 288. doi:10.1111/j.1600-048X.2008.04538.x