Columbia subject headings:
Harvard subject headings:
Luhmann, Niklas, 1927-1998
Luhmann, Niklas, 1927-1998--Dictionaries--German.
Luhmann, Niklas--Dictionaries--German.
Luhmann, Niklas.
Social systems.
Sociology--Dictionaries--German
Princeton subject headings:
Dictionaries.
Luhmann, Niklas, 1927-1998--Dictionaries--German.
Luhmann, Niklas, 1927-1998.
Social systems.
Sociology--Dictionaries--German.