Topogràfic
H - Social Science
94
K - Law
55
D - World History
51
J - Political Science
36
B - Filosofia, Psicologia, Religió
22
L - Education
18
P - Language and Literature
13
C - Historical Sciences
10
G - Geography, Anthropology, Recreation
10
N - Fine Arts
6
U - Military Science
5
R - Medicine
4
F - General American History
3
T - Technology
3
Z - Library Science
3
A - Treballs generalss
2
M - Music
2