Dias, E.A. and Oliveira, C.A. de (2006) “Psittacine sex determination by radioimunoassay (RIA) of sex steroids using fecal samples”, Brazilian Journal of Veterinary Research and Animal Science, 43(supl.), pp. 5–11. doi:10.11606/issn.1678-4456.bjvras.2006.26529.