Sleeman, C. W. (1880), Torpedoes and Torpedo Warfare, Portsmouth: Griffin & Co., pp. 137–138, which constitutes what is termed as the secret of the fish torpedo.
Roscoe 1967 Roscoe, Theodore (1967), Pig Boats: The True Story of the Fighting Submariners of World War II, New York: Bantam, OCLC22066288. Originally published in 1949 as United States Submarine Operations in World War II; Bantam version is abridged