TY  - GEN
AU  - Shrock, Robert R.
AU  - Twenhofel, Williams H.
TI  - Principles of invertebrate paleontology
U1  - 567 
PY  - 1953///
CY  - New Delhi
PB  - CBS Publishers & Distributors
KW  - Fossil chordata
KW  - Paleontology
ER  -