APA Edition Citation

Gregory, S. A., & Zeilik, M. (1998). Introductory astronomy and astrophysics (Ed.4.).

Chicago Edition Citation

Gregory, Stephen A., and Michael Zeilik. Introductory Astronomy and Astrophysics. Ed.4. Philadelphia, Saunders college publishing, 1998.

MLA Edition Citation

Gregory, Stephen A., and Michael Zeilik. Introductory Astronomy and Astrophysics. Ed.4. 1998.

Warning: These citations may not always be 100% accurate.