Classification
330 - Economics
2
331 - Labor economics
2
551 - Geology, hydrology & meteorology
2
004 - Data processing & computer science
1
305 - Social groups
1
306 - Culture & institutions
1
320 - Political science
1
323 - Civil & political rights
1
340 - Law
1
363 - Other social problems & services
1
364 - Criminology
1
550 - Earth sciences
1
591 - Specific topics in natural history
1
616 - Diseases
1
620 - Engineering & allied operations
1
640 - Home & family management
1
809 - History, description & criticism
1