Classification
361 - Social problems & social welfare in general
380 - Commerce, communications & transportation
600 - Technology
3
620 - Engineering & allied operations
630 - Agriculture & related technologies
2
700 - The arts; fine & decorative arts
2
000 - Computer science, information & general works
1
140 - Specific philosophical schools
1
333 - Economics of land & energy
1
581 - Specific topics in natural history
1
900 - History & geography
1