APA-referens (7:e uppl.)

Seeds, M. A., & Backman, D. (2018). Horizons: Exploring the universe (Fourteenth edition.). Cengage Learning.

Chicago-referens (17:e uppl.)

Seeds, Michael A., och Dana Backman. Horizons: Exploring the Universe. Fourteenth edition. Boston, MA, USA: Cengage Learning, 2018.

MLA-referens (9:e uppl.)

Seeds, Michael A., och Dana Backman. Horizons: Exploring the Universe. Fourteenth edition. Cengage Learning, 2018.