Topogràfic
P - Language and Literature
842
H - Social Science
226
B - Filosofia, Psicologia, Religió
180
D - World History
127
L - Education
90
F - General American History
87
J - Political Science
70
Q - Science
70
N - Fine Arts
42
E - United States History
38
G - Geography, Anthropology, Recreation
32
R - Medicine
27
T - Technology
26
K - Law
24
C - Historical Sciences
17
M - Music
7
Z - Library Science
7
U - Military Science
5
A - Treballs generalss
2
S - Agriculture
2