Hill, G. E.; Montgomerie, R.; Inouye, C. Y.; Dale, J. (Junho de 1994). «Influence of Dietary Carotenoids on Plasma and Plumage Colour in the House Finch: Intra- and Intersexual Variation». British Ecological Society. Functional Ecology. 8 (3): 343–350. JSTOR2389827. doi:10.2307/2389827
Hill, G. E.; Montgomerie, R.; Inouye, C. Y.; Dale, J. (Junho de 1994). «Influence of Dietary Carotenoids on Plasma and Plumage Colour in the House Finch: Intra- and Intersexual Variation». British Ecological Society. Functional Ecology. 8 (3): 343–350. JSTOR2389827. doi:10.2307/2389827