TY  - BOOK
AU  - Grigg,D.B.
TI  - The Agricultural systems of the World : : an evolutionary approach / 
SN  - 0521098432
U1  - 630.9 
PY  - 1974///
CY  - Cambridge : 
PB  - Cambridge University Press , 
KW  - Agriculture
N1  -  Includes bibliographical references
ER  -