Title: Periodic Orbits
Subjects: Astronomy, Astronomers, Biography, Orbits, Mathematics, Moulton planes, Three-body problem, Mechanics of particles and systems, History and biography -- Research exposition (monographs, survey articles), History and biography -- History of mathematics and mathematicians -- 19th century, History and biography -- History of mathematics and mathematicians -- 20th century, History and biography -- History of mathematics and mathematicians -- Universities, Mechanics of particles and systems-- Dynamics of a system of particles, including celestial mechanics -- Three-body problems, Astronomy and astrophysics -- History of astronomy and astrophysics .