TY  - BOOK
AU  - Gray, R. B., 
TI  - The agricultural tractor 1855-1950
AV  - S711 A37 
PY  - 1975///
CY  - St Joseph
PB  - American Society of Agricultural Engineers
KW  - Agricultural machinery
KW  - Tractors
KW  - History
KW  - United States
N1  - Includes index
ER  -