Topogràfic
H - Social Science
272
J - Political Science
149
F - General American History
96
K - Law
79
L - Education
48
P - Language and Literature
23
G - Geography, Anthropology, Recreation
21
Q - Science
16
R - Medicine
14
T - Technology
13
B - Filosofia, Psicologia, Religió
12
E - United States History
5
N - Fine Arts
4
D - World History
3
M - Music
3
A - Treballs generalss
1
C - Historical Sciences
1
S - Agriculture
1
U - Military Science
1
Z - Library Science
1