Gray, P. (1961). The encyclopedia of the biological sciences. Reinhold.
Cita Chicago (17th ed.)Gray, Peter. The Encyclopedia of the Biological Sciences. New Yoprk: Reinhold, 1961.
Cita MLA (9th ed.)Gray, Peter. The Encyclopedia of the Biological Sciences. Reinhold, 1961.
Atenció: Aquestes cites poden no estar 100% correctes.