article by H.E. Howard, published in The Zoologist, 4th series vol 3 (1899)

1920 edition by Henry Eliot Howard (London, John Murray edition)

New York, E. P. Dutton, 1920.

two-volume book, by Henry Eliot Howard, published in parts from 1907 and fully in 1914

part 1 of H. Eliot Howard's work, 1907