Topogràfic
D - World History
479
H - Social Science
199
P - Language and Literature
134
B - Filosofia, Psicologia, Religió
83
K - Law
77
L - Education
65
J - Political Science
62
N - Fine Arts
44
G - Geography, Anthropology, Recreation
32
T - Technology
32
R - Medicine
28
F - General American History
26
Q - Science
23
Z - Library Science
22
C - Historical Sciences
19
M - Music
9
U - Military Science
9
S - Agriculture
5
E - United States History
4
V - Naval Science
4
A - Treballs generalss
2