Columbia subject headings:
John XXI, Pope, -1277. Summulae logicales.
Logic--Early works to 1800.
Harvard subject headings:
John XXI, Pope, -1277. Summulae logicales.
Logic--Early works to 1800
Princeton subject headings:
John XXI, Pope, -1277. Summulae logicales.
Logic--Early works to 1800.