Columbia subject headings:
Agricultural libraries--United States--Periodicals.
Agricultural libraries.
Agriculture--Bibliography--Periodicals.
Agriculture--Information services--United States--Periodicals.
Agriculture--United States--Information services--Periodicals.
Harvard subject headings:
Agricultural libraries--United States--Periodicals.
Agriculture--Bibliography--Periodicals.
Agriculture--United States--Information services--Periodicals.
Princeton subject headings:
Agricultural libraries--United States--Periodicals.
Agriculture--Bibliography--Periodicals.
Agriculture--United States--Information services--Periodicals.
Periodicals.