Russell (2012). „Dr. George Murray Levick (1876–1956): Unpublished notes on the sexual habits of the Adélie penguin”. Polar Record48 (4), 1. o. DOI:10.1017/S0032247412000216.
Bagshawe, T. W. (1938). „Notes on the Habits of the Gentoo and Ringed or Antarctic Penguins”. The Transactions of the Zoological Society of London24 (3), 209. o. DOI:10.1111/j.1096-3642.1938.tb00391.x.
Herodotus (c. 440 BC). The Histories (Book 2) (2001. július 1.) „The wives of men of rank when they die are not given at once to be embalmed, nor such women as are very beautiful or of greater regard than others, but on the third or fourth day after their death (and not before) they are delivered to the embalmers. They do so about this matter in order that the embalmers may not abuse their women, for they say that one of them was taken once doing so to the corpse of a woman lately dead, and his fellow-craftsman gave information.”
