Reference

Lynda P. Dunkel, Natasha Arora, Maria A van Noordwijk, Sri Suci Utami Atmoko, Angga Prathama Putra, Michel Krützen, Carel P van Schaik (2013): Variation in developmental arrest among male orangutans: a comparison between a Sumatran and a Bornean population – Frontiers in Zoology – 2013: 0001-12-0011.