Columbia subject headings:
Document delivery--United States.
Information services--United States.
Interlibrary loans--United States.
Library surveys--United States.
Harvard subject headings:
Document delivery--United States.
Information services--United States.
Interlibrary loans--United States.
Library surveys--United States.
Princeton subject headings:
Document delivery--United States.
Information services--United States.
Interlibrary loans--United States.
Library surveys--United States.