APA (7th ed.) Citation

Helicon (Firm) & ebrary, Inc. (2006). Astronomy. Helicon.

Chicago Style (17th ed.) Citation

Helicon (Firm) and Inc ebrary. Astronomy. Abingdon, Oxon: Helicon, 2006.

MLA (9th ed.) Citation

Helicon (Firm) and Inc ebrary. Astronomy. Helicon, 2006.

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