Topogràfic
H - Social Science
289
F - General American History
177
J - Political Science
162
K - Law
112
P - Language and Literature
49
L - Education
48
G - Geography, Anthropology, Recreation
26
B - Filosofia, Psicologia, Religió
24
Q - Science
17
T - Technology
17
R - Medicine
14
E - United States History
10
N - Fine Arts
6
D - World History
5
M - Music
5
C - Historical Sciences
2
Z - Library Science
2
A - Treballs generalss
1
S - Agriculture
1
U - Military Science
1