Vanzolini, P.E. 1967. Notes on the nesting behaviour of Podocnemis expansa in the Amazon valley (Testudines, Pelomedusidae). Papéis Avulsos de Zoologia. 20, 1-21 (1967) (Jul. 1967), 191–215. DOI:https://doi.org/10.11606/0031-1049.1967.20p191-215.