Classification
D - World History
46
Q - Science
22
S - Agriculture
12
A - General Works
11
H - Social Science
8
L - Education
4
N - Fine Arts
4
P - Language and Literature
4
T - Technology
4
B - Philosophy, Psychology, Religion
3
G - Geography, Anthropology, Recreation
2
E - United States History
1
K - Law
1
R - Medicine
1