Regional changes in grain production : an application of  spatial linear programming /
Egbert, Alvin C.(Alvin Charles),1922-author.
Heady, Earl O.(Earl Orel),1916-1986,author.
Brokken, Ray F.,author.
Iowa State University.Agricultural and Home Economics Experiment Station.
Iowa State University.Department of Economics and Sociology.
Iowa State University.Center for Agricultural and Economic Adjustment.
United States.Department of Agriculture.Economic Research Service.Farm Economics Division
Title from front cover.
Includes bibliographical references (page 1016).