Columbia subject headings:
Harvard subject headings:
Germany--History--1273-1517.
Germany--History--Interregnum, 1254-1273.
Princeton subject headings:
Constitutional history--Germany.
Germany--History--1273-1517.
Germany--History--Hohenstaufen, 1138-1254.
Germany--History--Interregnum, 1254-1273.
Holy Roman Empire--History--1273-1517.