Classification
P - Language and Literature
11,027
Q - Science
366
T - Technology
181
S - Agriculture
37
G - Geography, Anthropology, Recreation
19
H - Social Science
18
N - Fine Arts
12
R - Medicine
7
C - Historical Sciences
3
D - World History
3
L - Education
2
M - Music
2
A - General Works
1
B - Philosophy, Psychology, Religion
1
E - United States History
1
F - General American History
1
J - Political Science
1