Kohler, R. E. Subspecies classification and biological survey, 1850s-1930s: Robert E. Kohler. Spaces of classification.(2003).
Chicago Style (17. basım) AtıfKohler, Robert E. "Subspecies Classification and Biological Survey, 1850s-1930s: Robert E. Kohler." Spaces of Classification.(2003) .
MLA (8th ed.) AtıfKohler, Robert E. "Subspecies Classification and Biological Survey, 1850s-1930s: Robert E. Kohler." Spaces of Classification.(2003), .
Uyarı: Bu alıntı herzaman %100 doğru olmayabilir..