24,22=7; 24,47=8; 26,30=11; 27,26=13; 28,15=16; 28,16=15; 28,19=14; 29,27=18; 29,38=19; 31,44=21; 32,7=22; 32,26=26; 32,35=24; 32,52=25; 33,34=27; 33,51=28; 35,7=30; 35,33=31; 53,47=32; 35,55=33; 35,56=34; 36,8=35; 36,35=36; 37,8=37; 39,3=39; 40,3=41; 40,34=43; 40,35=44; 41,20=45; 42,10=48; 42,18=49; 43,8=52; 44,24=54; 45,22=56; 45,25=57 von: Pennsylvania State College. Mineral Industries Experiment Station: Mineral Industries Experiment Station bulletin
46,20=62; 47,18=63 von: Pennsylvania State College. Department of Engineering Research: Department of Engineering Research bulletin
4,4=55; 5,4=56; 6,4=57; 7,3=58; 8,2=59; 9,2=60; 10,2=61; 15,7=66; 16,5=67; 26,14=1932/33; 27,14=1933/34; 44,1=1950/51 von: Pennsylvania State College: General catalogue
30,30=1,2 von: Pennsylvania State College: The Pennsylvania State College studies
43,13=2; 44,16=3 von: Conference on the Administration of Research: Proceedings of the ... National Conference on the Administration of Research (ISSN: 0090-2780)
43,13=30; 44,16=31 von: Pennsylvania State College. Engineering Experiment Station: Technical bulletin of the Engineering Experiment Station
