TY  - BOOK
AU  - Shrock,Robert R.
AU  - Twenhofel, William H. 
TI  - Principles of invertebrate paleontology
U1  - 562 22
PY  - 1953///
CY  - New York
PB  - McGraw-Hill
KW  - Invertebrates, Fossil
N1  - Includes bibliographical references & index
ER  -