Classification
100 - Philosophy & psychology
370 - Education
2
380 - Commerce, communications & transportation
600 - Technology
2
000 - Computer science, information & general works
1
140 - Specific philosophical schools
1
300 - Social sciences
1
320 - Political science
1
500 - Natural sciences & mathematics
1
620 - Engineering & allied operations
1
900 - History & geography
1