Topogràfic
P - Language and Literature
108
H - Social Science
83
D - World History
44
J - Political Science
38
K - Law
36
B - Filosofia, Psicologia, Religió
23
L - Education
15
G - Geography, Anthropology, Recreation
11
C - Historical Sciences
9
N - Fine Arts
5
T - Technology
4
A - Treballs generalss
3
F - General American History
3
U - Military Science
3
Z - Library Science
3
M - Music
2
R - Medicine
2
E - United States History
1
Q - Science
1
V - Naval Science
1