Columbia subject headings:
Agricultural extension work--Iran--Congresses.
Agricultural extension work--Pakistan--Congresses.
Agricultural extension work--Turkey--Congresses.
Harvard subject headings:
Agricultural extension work--Iran--Congresses.
Agricultural extension work--Pakistan--Congresses.
Agricultural extension work--Turkey--Congresses.
Princeton subject headings:
Agricultural extension work--Iran--Congresses.
Agricultural extension work--Pakistan--Congresses.
Agricultural extension work--Turkey--Congresses.