Topogràfic
H - Social Science
462
R - Medicine
301
Q - Science
279
P - Language and Literature
194
K - Law
188
T - Technology
171
L - Education
138
D - World History
125
B - Filosofia, Psicologia, Religió
90
G - Geography, Anthropology, Recreation
81
A - Treballs generalss
76
S - Agriculture
66
F - General American History
60
J - Political Science
57
Z - Library Science
51
N - Fine Arts
45
M - Music
26
E - United States History
22
C - Historical Sciences
21
U - Military Science
6