Kroeber, E., Wolff, W. H., & Bleifeld, M. (1965). Key: Biology, second edition. Workbook and laboratory manual. D. C. Heath and Co..
Lua i Stíl Chicago (17ú heag.)Kroeber, Elsbeth, Walter H. Wolff, agus Maurice Bleifeld. Key: Biology, Second Edition. Workbook and Laboratory Manual. [Boston]: D. C. Heath and Co., 1965.
Lua MLA (8ú heag.)Kroeber, Elsbeth, et al. Key: Biology, Second Edition. Workbook and Laboratory Manual. D. C. Heath and Co., 1965.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.