Template:Ref-Semon1901
From Embryology
Semon R. Normal plates of the development of vertebrates (Normentafeln zur Entwicklungsgeschichte der Wirbelthiere) Vol. 3. Normal Plates of the Development of the Lungfish Embryo. (3. Heft Normentafeln zur Entwicklungsgeschichte ceratodus forsteri) (1901) Fisher, Jena., Germany.