Cita APA (7a ed.)

Ptolemy, 2. c., Ptolomeo, C., Copernicus, N., Kepler, J., Taliaferro, R. C., Wallis, C. G., & Kepler, J. (1952). The almagest. Encyclopædia Britannica.

Cita Chicago Style (17a ed.)

Ptolemy, 2nd cent, Claudio Ptolomeo, Nicolaus Copernicus, Johannes Kepler, Robert Catesby Taliaferro, Charles Glenn Wallis, y Johannes Kepler. The Almagest. Chicago,: Encyclopædia Britannica, 1952.

Cita MLA (8a ed.)

Ptolemy, 2nd cent, et al. The Almagest. Encyclopædia Britannica, 1952.