Classification
520 - Astronomy & allied sciences
241
629 - Other branches of engineering
23
500 - Natural sciences & mathematics
16
530 - Physics
13
523 - Specific celestial bodies & phenomena
5
551 - Geology, hydrology & meteorology
2
301 - Sociology & anthropology
1
509 - Historical, geographic & persons treatment
1
550 - Earth sciences
1
571 - Physiology & related subjects
1
576 - Genetics & evolution
1
577 - Ecology
1
600 - Technology
1
900 - History & geography
1