Armstrong, David L. Farm machinery : costs performance rates, and combinations, Southern San Joaquin Valley, California / David L. Armstrong & Edwin Faris - California : California University , 1964 - v, 73p. : ill. ; 26 cm. - Giannini Foundation research report . Includes bibliographical references. Subjects--Topical Terms: Agriculture--San Joaquin ValleyMechanization Dewey Class. No.: 631.3 / ARM