TY  - BOOK
AU  - John H. Martin
AU  -  Warren H. Leonard, 
TI  - Principles of field crop production
U1  - 633 
PY  - 1949///
CY  - New York
PB  - Mcmillan Company
N1  - John H. Martin & Warren H. Leonard: Principles of field crop production.  New York.  Mcmillan Company, 1949.--(633MAR)
ER  -