TY  - BOOK
AU  - Langdon John
TI  - Horses, oxen and technological innovation :  The us   
SN  - 0521267722
U1  - X9(J)0gF.3.J00<-E66, M6 
PY  - 1986///
CY  - Cambridge
PB  - Cambridge university press        
KW  - Agriculture Industries
N1  - Past and present publications
ER  -