APA

Parker T. J., Haswell W. A. & Marshall A. J. (19). A text-book of zoology. New York: St. Martin's Press.

Chicago

Parker T Jeffery, Haswell William A and Marshall Alan John. 19. A text-book of zoology. New York: St. Martin's Press.

Harvard

Parker T. J., Haswell W. A. and Marshall A. J. (19). A text-book of zoology. New York: St. Martin's Press.

MLA

Parker T Jeffery, Haswell William A and Marshall Alan John. A text-book of zoology. New York: St. Martin's Press. 19.