Marketing Abstracts - Penn, William S. and Regan, William J. and Schendel, D. E. and Bergstrom, Marie (Journal of Marketing, 1967)
https://katalog.adlr.link/Record/ai-49-aHR0cDovL2R4LmRvaS5vcmcvMTAuMTE3Ny8wMDIyMjQyOTY3MDMxMDAzMTc