Tracking the ovarian cycle in black-and-gold howlers (Alouatta caraya) by measuring fecal steroids and observing vaginal bleeding - Kugelmeier, Tatiana; Valle, Rodrigo del Rio do; Guimaraes, Marcelo Alcindo de Barros Vaz; Muniz, José Augusto Pereira Carneiro; Monteiro, Frederico Ozanan Barros; Oliveira, Cláudio Alvarenga de (International Journal of Primatology, 2011)