Purdom, P. . . . . . . . . W. (1971). Environmental health. Academic Press, a subsidiary of Harcourt Brace Jovanovich.
Cita Chicago (17th ed.)Purdom, P Walton. Environmental Health. New York: Academic Press, a subsidiary of Harcourt Brace Jovanovich, 1971.
Cita MLA (9th ed.)Purdom, P Walton. Environmental Health. Academic Press, a subsidiary of Harcourt Brace Jovanovich, 1971.
Atenció: Aquestes cites poden no estar 100% correctes.