Classification
D - World History
44
R - Medicine
16
B - Philosophy, Psychology, Religion
5
M - Music
5
F - General American History
4
A - General Works
3
C - Historical Sciences
3
P - Language and Literature
3
S - Agriculture
3
E - United States History
2
H - Social Science
2
J - Political Science
1
Q - Science
1
T - Technology
1