Classification
540 - Chemistry & allied sciences
8
620 - Engineering & allied operations
4
667 - Cleaning, color & coating technologies
3
025 - Library operations
2
547 - Organic chemistry
2
621 - Applied physics
2
660 - Chemical engineering
2
306 - Culture & institutions
1
371 - Schools & their activities; special education
1
507 - Education, research & related topics
1
542 - Techniques, equipment & materials
1
543 - Analytical chemistry
1
577 - Ecology
1
581 - Specific topics in natural history
1
674 - Lumber processing, wood products & cork
1