„Sula” változatai közötti eltérés

|author2=Anderson, D. J.|author3=Steeves, T. E.|author4=Jones, H.|author5=Schreiber, E. A.

| title = Molecular Support for Species Status of the Nazca Booby

| volume = 119

| issue = 3

| publisher = Department of Biology, Queen's University

| location = Kingston, Ontario

| date = July 2002

| url = http://www.bioone.org/perlserv/?request=get-abstract&doi=10.1642%2F0004-8038(2002)119%5B0820%3AMSFSSO%5D2.0.CO%3B2