Columbia subject headings:
Husserl, Edmund, 1859-1938.
Luhmann, Niklas, 1927-1998.
Phenomenology.
Social systems.
System theory.
Harvard subject headings:
Husserl, Edmund, 1859-1938
Luhmann, Niklas, 1927-1998
Phenomenology.
Social systems.
System theory.
Princeton subject headings:
Husserl, Edmund, 1859-1938.
Luhmann, Niklas, 1927-1998.
Phenomenology.
Social systems.
System theory.