Número de Clasificación
E - United States History
50
S - Agriculture
21
B - Philosophy, Psychology, Religion
20
R - Medicine
20
P - Language and Literature
19
A - General Works
7
C - Historical Sciences
4
M - Music
4
Q - Science
4
T - Technology
3
F - General American History
2
D - World History
1
H - Social Science
1
L - Education
1
U - Military Science
1