Classification
T - Technology
90
R - Medicine
55
B - Philosophy, Psychology, Religion
41
P - Language and Literature
41
H - Social Science
24
M - Music
24
D - World History
14
A - General Works
13
E - United States History
9
C - Historical Sciences
6
S - Agriculture
5
Q - Science
3
K - Law
2
F - General American History
1