Vigors, Nicholas Aylward (April 1825). "On a new genus of Falconidæ". Sketches in Ornithology. The Zoological Journal. 2 (5): 65–70. The description of G. swainsonii is on pages 68–70, formal Latin description begins on p. 69. Biodiversity Heritage Library holds two digitized copies: one from London Museum of Natural History [1], and the other from Smithsonian Libraries [2]
