グロージャーの法則
Das Abändern der Vögel durch Einfluss des Klimas [The Evolution of Birds Through the Impact of Climate]. Breslau: August Schulz. pp. 11–24. ISBN 978-3-8364-2744-9. OCLC 166097356. https://books.google.com/?id=IwwAAAAAQAAJ&pg=PA11
Stresemann, Erwin; Epstein, Hans J. (translator); Epstein, Cathleen (translator) (August 1975). G. William Cottrell. ed. Ornithology: from Aristotle to the present. Cambridge, MA: Harvard University Press. p. 70. ISBN 978-0-674-64485-4. LCCN 74-25035. OCLC 1499768. https://books.google.com/?id=RrS1AAAAIAAJ&pg=PA70
Zink, RM; Remsen, JV (1986). “Evolutionary processes and patterns of geographic variation in birds”. Current Ornithology 4: 1–69.