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(EN) Friesen, V.L., Anderson, D.J., Steeves, T.E., Jones, H. e Schreiber, E.A., [0820:MSFSSO2.0.CO;2 Molecular Support for Species Status of the Nazca Booby (Sula granti)], in Auk, vol. 119, n. 3, 2002, pp. 820–6, DOI:10.1642/0004-8038(2002)119[0820:MSFSSO]2.0.CO;2.