Development of the agricultural tractor in the United States.

Pt. 2 published without series title or numbering by the American Society of Agricultural Engineers, 1958.

Development of the agricultural tractor in the United States,

A limited ed. was compiled and printed by the Agricultural Engineering Research Branch, Agricultural Research Service in 1954.

Suggested unit course in farm tractor maintenance ...

"Prepared in cooperation with the United States Office of education."--p. [2] of cover.