Iowa. State Planning Board. Committee on Land UtilizationNegative. "Iowa state plan." "Project 1030." "1030-15."1 map : black line ; 84 x 115 cm663975374; index.cpdMAPG4151_J61_1931_I6islandora: testiadep_1763https://digital.lib.uiowa.edu/node/412897engUniversity of Northern IowaPublicShipment of corn & oats: percent net shipment of corn & oats combined to total production by regions 1928-1931MapsIowa1920-19301930-1940University of Iowa