Kroeber, E., Wolff, W. H., & Bleifeld, M. (1965). Key: Biology, second edition. Workbook and laboratory manual. D. C. Heath and Co..
Dyfyniad Arddull ChicagoKroeber, Elsbeth, Walter H. Wolff, and Maurice Bleifeld. Key: Biology, Second Edition. Workbook and Laboratory Manual. [Boston]: D. C. Heath and Co., 1965.
Dyfyniad MLAKroeber, Elsbeth, et al. Key: Biology, Second Edition. Workbook and Laboratory Manual. D. C. Heath and Co., 1965.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.