Fraknoi, A., & Morrison, D. W. (2001). Voyages through the universe (2nd ed.). Harcourt College Publishers.
استشهاد بنمط شيكاغوFraknoi, Andrew, و David Wolff Morrison. Voyages Through the Universe. 2nd ed. Philadelphia: Harcourt College Publishers, 2001.
MLA استشهادFraknoi, Andrew, و David Wolff Morrison. Voyages Through the Universe. 2nd ed. Harcourt College Publishers, 2001.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.