Delacour, Jean T., and Ernst Mayr, Birds of the Philippine Islands. New
York: The Macmillan Co., 1946.
Hachisuka, The Hon. Masaiya, The Birds of the Philippine Islands.
London: H. F. Witherby, 1931–1935.
Thomson, A. Landsborough, A New Dictionary of Birds. New York:
McGraw-Hill, 1964.