Columbia subject headings:
Agriculture--Statistics--Study and teaching--United States--Handbooks, manuals, etc.
Teachers--United States--Handbooks, manuals, etc.
Harvard subject headings:
Agriculture--Statistics--Study and teaching--United States--Handbooks, manuals, etc.
Teachers--United States--Handbooks, manuals, etc.
United States--Census--Statistics--Study and teaching--Handbooks, manuals, etc.
Princeton subject headings: