Deon C. Greer, project director ; Klaus D. Gurgel, cartographic editor ; Wayne L. Wahlquist, editor, Howard A. Christy, associate editor ; Gary B. Peterson, photography
a cooperative project of the three Commonwealth Research Universities ; Temple University, editors, David J. Cuff, William J. Young ; University of Pittsburgh, [editor], Edward K. Muller ; The Pennsylvania State University, [editors] Wilbur Zelinsky, Ronald F. Abler