Columbia subject headings:
Harvard subject headings:
Astronomers--Denmark--Biography.
Astronomers--Germany.
Brahe, Tycho, 1546-1601.
Kepler's laws.
Kepler, Johannes, 1571-1630.
Planetary theory.
Princeton subject headings:
Astronomers--Denmark--Biography.
Astronomers--Germany.
Brahe, Tycho, 1546-1601.
Kepler's laws.
Kepler, Johannes, 1571-1630.
Planetary theory.