Columbia subject headings:
Langland, William, 1330?-1400?
Mysticism in literature.
Harvard subject headings:
Langland, William, 1330?-1400?
Langland, William, 1330?-1400? Piers Plowman.
Mysticism in literature.
Mysticism--England--History--Middle Ages, 600-1500
Princeton subject headings: