Classification
307 - Communities
1
320 - Political science
1
333 - Economics of land & energy
1
339 - Macroeconomics & related topics
1
347 - Civil procedure & courts
1
363 - Other social problems & services
1
510 - Mathematics
1
519 - Probabilities & applied mathematics
1
530 - Physics
1
621 - Applied physics
1
623 - Military & nautical engineering
1
792 - Stage presentations
1
909 - World history
1
919 - Geography of & travel in other areas
1
970 - History of North America
1
980 - History of South America
1