Columbia subject headings:
Social service--Dictionaries.
Social service--Societies, etc.--Directories.
Social service.
Harvard subject headings:
Social service--Dictionaries
Social service--Societies, etc.--Directories
Social service.
Princeton subject headings:
Dictionaries.
Directories.
Periodicals.
Social service--Dictionaries.
Social service--Periodicals.
Social service--Societies, etc.--Directories.