Topogràfic
H - Social Science
3,706
K - Law
260
J - Political Science
253
F - General American History
251
S - Agriculture
98
L - Education
71
G - Geography, Anthropology, Recreation
67
T - Technology
58
C - Historical Sciences
37
R - Medicine
29
D - World History
25
Q - Science
20
B - Filosofia, Psicologia, Religió
19
E - United States History
17
P - Language and Literature
16
N - Fine Arts
11
Z - Library Science
4
A - Treballs generalss
3
U - Military Science
2
V - Naval Science
2
M - Music
1