APA (7th ed.) Citation

Ptolemy, a. 2. c., Peters, C. H. F., & Knobel, E. B. (1915). Ptolemy's catalogue of stars: A revision of the Almagest. The Carnegie Institution of Washington.

Chicago Style (17th ed.) Citation

Ptolemy, active 2nd century, C. H. F. Peters, and E. B. Knobel. Ptolemy's Catalogue of Stars: A Revision of the Almagest. [Washington, D.C.]: The Carnegie Institution of Washington, 1915.

MLA (9th ed.) Citation

Ptolemy, active 2nd century, et al. Ptolemy's Catalogue of Stars: A Revision of the Almagest. The Carnegie Institution of Washington, 1915.