Topogràfic
L - Education
66
H - Social Science
57
Q - Science
20
R - Medicine
17
P - Language and Literature
9
G - Geography, Anthropology, Recreation
8
T - Technology
8
B - Filosofia, Psicologia, Religió
7
J - Political Science
6
K - Law
6
Z - Library Science
6
N - Fine Arts
4
A - Treballs generalss
3
D - World History
2
S - Agriculture
1