Classification
330 - Economics
15
972 - Middle America; Mexico
4
338 - Production
3
305 - Social groups
2
320 - Political science
2
331 - Labor economics
2
301 - Sociology & anthropology
1
306 - Culture & institutions
1
332 - Financial economics
1
335 - Socialism & related systems
1
337 - International economics
1
355 - Military science
1
362 - Social welfare problems & services
1
382 - International commerce
1
917 - Geography of & travel in North America
1
978 - Western United States
1