Diffusion of an innovation in an urban system [microform] : the spread of planned regional shopping centers in the United States, 1949-1968 / Yehoshua S. Cohen. Cohen, Yehoshua S., 1937- Microfilm 50193 (H) 301.243 COD Bibliography: p. 131-136. Microfilm. Chicago, Ill. : University of Chicago, Joseph Regenstein Library, Dept. of Photoduplication, 1973. 1 microfilm reel ; 35 mm. Chicago : Dept. of Geography, University of Chicago, 1972. 1973. 1972. 1973 Text ix, 136 p. : 1 microfilm reel ; 35 mm. eng Research paper / University of Chicago, Department of Geography ; no. 140 Research paper (University of Chicago. Department of Geography) ; no. 140.