Fraknoi, A., & Morrison, D. W. (2001). Voyages through the universe (2nd ed.). Harcourt College Publishers.
Chicago Edition CitationFraknoi, Andrew, and David Wolff Morrison. Voyages Through the Universe. 2nd ed. Philadelphia: Harcourt College Publishers, 2001.
ציטוט MLAFraknoi, Andrew, and David Wolff Morrison. Voyages Through the Universe. 2nd ed. Harcourt College Publishers, 2001.
אזהרה: ציטוטים אלה לעיתים לא מדויקים ב 100%.