Reference
Christian Welker, Hella Höhmann-Kröger, Gerald A. Doyle (1992): Social relations in groups of Black-capped capuchin monkeys,
(Cebus apella) in captivity: sibling relations from the second to
the fifth year of life – Mammalian Biology (früher Zeitschrift für Säugetierkunde) – 57: 269 - 274.