American Heritage Children's Dictionary (American Heritage Dictionary): American Heritage Publishing Staff: 9780395857397: Amazon.com: Books
Darwin, C. R. 1876. Fritz Müller on Brazil kitchen middens, habits of ants, etc. Nature. A Weekly Illustrated Journal of Science. 13 (17 February): 304-5.
Wallace, A. R. 1900. Studies scientific and social. London: Macmillan & Co., Ltd. And New York: The Macmillan Co. Volume 2.