Author
Pennsylvania. Bureau of Topographic and Geologic Survey
181
Culinary Collection (University of Pennsylvania)
120
Chef Fritz Blank Culinary Archive and Library (University of Pennsylvania)
99
United States. Bureau of Mines
83
Geological Survey (U.S.)
76
Pennsylvania. Department of Environmental Resources
73
Pennsylvania. Department of Transportation
64
Susquehanna River Basin Commission
59
Pennsylvania. Department of Environmental Protection
40
Pennsylvania. Department of Transportation. Bureau of Planning and Research
35
Pennsylvania Transportation Institute
34
Pennsylvania Historical and Museum Commission
33
Fettke, Charles R. (Charles Reinhard), 1888-1959
32
Lytle, William S.
32
Pennsylvania State University. Institute for Research on Land and Water Resources
29
United States. Army. Corps of Engineers. Pittsburgh District
27
Temple University. School of Law
23
Chem-Nuclear Systems, Inc
22
Pennsylvania. General Assembly. Legislative Budget and Finance Committee
22
America's Industrial Heritage Project
21
Ash, S. H. (Simon Harry), 1889-
21
Whisker, James B., 1939-
21
California State College (Pa.). Dept. of Industrial Arts
20
Springirth, Kenneth C.
20
U.S. Nuclear Regulatory Commission. Office of Nuclear Reactor Regulation
20
United States. Army. Corps of Engineers. Philadelphia District
20
United States. Federal Highway Administration
20
Delaware Valley Regional Planning Commission
19
O'Neill, Bernard J., 1920-
19
Geological Survey (U.S.). Water Resources Division
18
Sisler, James D. (James Donaldson), 1894-
18
Ashburner, Charles A. (Charles Albert), 1854-1889
17
Center for Rural Pennsylvania
17
McGlade, William G.
17
Pennsylvania. Department of Forests and Waters
17
Skema, Viktoras W.
17
Historic American Buildings Survey/Historic American Engineering Record
16
Pennsylvania Aeronautics Commission
16
Pennsylvania. Department of Highways
16
Rohrbeck, Benson W.
16
Pennsylvania
15
Pennsylvania. General Assembly. Joint State Government Commission
15
United States. Army. Corps of Engineers. Baltimore District
15
Ashley, Geo. H. (George Hall), 1866-1951
14
California State College (Pa.). Division of Graduate Studies
14
Nancy Klavans Cookery Collection (University of Pennsylvania)
14
Pennsylvania Cable Network
14
Pennsylvania. Bureau of Water Quality Management
14
United States. President's Commission on the Accident at Three Mile Island
14
Woman's Institute of Domestic Arts and Sciences
14
more ...