Classification
D - World History
29
F - General American History
17
M - Music
14
P - Language and Literature
9
T - Technology
8
Z - Library Science
7
J - Political Science
6
A - General Works
5
B - Philosophy, Psychology, Religion
4
E - United States History
2
R - Medicine
2
C - Historical Sciences
1
H - Social Science
1
K - Law
1
S - Agriculture
1