Columbia subject headings:
Harvard subject headings:
Freud, Sigmund, 1856-1939
Friendship in literature.
Friendship--History.
Friendship--Philosophy.
Kafka, Franz, 1883-1924--Criticism and interpretation.
Nietzsche, Friedrich Wilhelm, 1844-1900
Princeton subject headings:
Friendship in literature.
Friendship--History.
Friendship--Philosophy.