Cita APA (7a ed.)

Moulton, F. (1920). Periodic orbits. Carnegie Institution.

Cita Chicago Style (17a ed.)

Moulton, F.R. Periodic Orbits. Washington: Carnegie Institution, 1920.

Cita MLA (9a ed.)

Moulton, F.R. Periodic Orbits. Carnegie Institution, 1920.