Columbia subject headings:
Chrétien, de Troyes, active 12th century. Perceval le Gallois.
Grail--Legends--History and criticism.
Harvard subject headings:
Chrétien, de Troyes, active 12th century. Perceval le Gallois.
Grail--Legends--History and criticism
Princeton subject headings:
Chrétien, de Troyes, active 12th century. Perceval le Gallois.
Grail--History and criticism.