Columbia subject headings:
Grail--Romances--History and criticism.
Quests (Expeditions) in literature.
Harvard subject headings:
European literature--20th century--Themes, motives.
Grail--Legends--History and criticism
Quests (Expeditions) in literature.
Princeton subject headings:
European literature--20th century--Themes, motives.
Grail--Legends--History and criticism.