Classification
333 - Economics of land & energy
2
370 - Education
380 - Commerce, communications & transportation
400 - Language
2
500 - Natural sciences & mathematics
900 - History & geography
2
100 - Philosophy & psychology
1
300 - Social sciences
1
320 - Political science
1
540 - Chemistry & allied sciences
1
600 - Technology
1
610 - Medicine & health
1
620 - Engineering & allied operations
1