TY  - BOOK
AU  - Shrock, Robert R; Twenhofel, William H
TI  - Principles of invertebrate paleontology
U1  - 560.45  SHR-P 
PY  - 1953///
CY  - McGraw-Hill book Co, Inc., NewYork
KW  - Paleoecology and fossils of specific environments
ER  -