Topogràfic
P - Language and Literature
52
D - World History
26
H - Social Science
26
J - Political Science
19
F - General American History
15
K - Law
14
B - Filosofia, Psicologia, Religió
9
N - Fine Arts
8
G - Geography, Anthropology, Recreation
7
L - Education
7
Q - Science
5
R - Medicine
5
C - Historical Sciences
2
A - Treballs generalss
1
M - Music
1
T - Technology
1
Z - Library Science
1