The Ancestry of Modern Amphibia: A Review of the Evidence

by Theodore H. Eaton

1950. Tetrapods from the Pennsylvanian nodules from Mazon Creek, Illinois. Am. Jour. Sci., 248:833-873.

Hecht, M. E.

1957. A case of parallel evolution in salamanders. Proc. Zool. Soc. Calcutta, Mookerjee Mem.:283-292.

Holmgren, N.

1933. On the origin of the tetrapod limb. Acta Zool., 14:185-295.

1939. Contributions to the question of the origin of the tetrapod limb. Acta Zool., 20:89-124.

1949a. Contributions to the question of the origin of tetrapods. Acta Zool., 30:459-484.

1949b. On the tetrapod limb problem again. Acta Zool., 30:485-508.

Herre, W.

1935. Die Schwanzlurche der mitteleocänen (oberlutetischen) Braunkohle des Geiseltales und die Phylogenie der Urodelen unter Einschluss der fossilen Formen. Zoologica, 33:87, 1-5.