Van't Hof, Thomas J. Verhaltensphysiologie, Seewiesen, Max Planck Institut für Ornithologie, Max Planck Society;
Hau, M., Romero, L. M., Brawn, J. D., & Van't Hof, T. J. (2002). Effect of polar day on plasma profiles of melatonin, testosterone, and estradiol in high-Arctic Lapland Longspurs. General and Comparative Endocrinology, 126(1), 101-112. doi:10.1006/gcen.2002.7776.