Crockett, Gary (2011). «Humpback Whale Calves». Humpback whales Australia. Arkivert frå originalen 20. mars 2018. Henta 28. august 2013.
worldcat.org
Lindburg et al. 1972, s. 319-320 Lindburg, D. G.; Lester; Dessez; Hazell (1972), «Licking of the Neonate and Duration of Labor in Great Apes and Man», American Anthropologist, New Series 74 (3): 318–325, ISSN0002-7294
Munn C; Fernandez M (1997). «Infant development». I Carol Sodaro. Orangutan species survival plan husbandry manual. Chicago: Chicago Zoological Park. s. 59–66. OCLC40349739.