TY  - BOOK
AU  - Twenhofel,William H.
AU  - Shrock,Robert R.
TI  - Principles of invertebrate paleontology
T2  - McGraw-Hill series in geology
U1  - 562 
PY  - 1953///
CY  - New York
PB  - McGraw-Hill
KW  - Invertebrates, Fossil
N1  - "A revised and enlarged edition of Twenhofel and Shrock, Invertebrate paleontology."
ER  -