(en) Peale, T.R., 1849. United States Exploring Expedition during the years 1838, 1839, 1840, 1841, 1842 (etc.). Volume 8, Mammalia and Ornithology. C. Sherman, Philadelphia p. 150 BHL
(en) Pratt, H.D. & J.C. Mittermeier, 2016.Notes on the natural history, taxonomy, and conservation of the endemic avifauna of the Samoan Archipelago. The Wilson Journal of Ornithology 128(2):217-241. DOI:10.1676/wils-128-02-217-241.1