Classification
S - Agriculture
30
H - Social Science
22
M - Music
18
T - Technology
14
L - Education
10
Q - Science
9
J - Political Science
5
K - Law
5
A - General Works
4
D - World History
4
R - Medicine
4
C - Historical Sciences
3
G - Geography, Anthropology, Recreation
3
N - Fine Arts
3
P - Language and Literature
3
U - Military Science
2
E - United States History
1