Title: Systematics of Lower and Lower Middle Devonian species of the trilobite Phacops Emmrich in North America
First published: 1973
Subjects: Paleontology, Phacops
Places: North America
Time periods: Devonian
LC classification: QH1 .A4 vol. 151, art. 4, QE823.P5 .A4 vol. 151, art. 4