R. C. Murphy, 1936, _Oceanic Birds of South America_, Vol. 1, p. 372 (penguins). U. M. Grigg, 1950, Brit. Birds, Vol. 43, pp. 11-13 (graveyard in hollow tree). G. Simmons, 1927, _Nat. Geog. Mag._, Vol. 52, p. 27 (petrel bones on Cima).