Topogràfic
F - General American History
81
K - Law
33
P - Language and Literature
26
H - Social Science
17
J - Political Science
13
B - Filosofia, Psicologia, Religió
12
E - United States History
5
G - Geography, Anthropology, Recreation
5
T - Technology
4
D - World History
2
M - Music
2
N - Fine Arts
2
C - Historical Sciences
1
Q - Science
1
Z - Library Science
1