International, W. B. C. (1978). Science Year: The world book science annual. U.S.A.
Chicago Edition CitationInternational, World Book Childcraft. Science Year: The World Book Science Annual. Chicago: U.S.A, 1978.
ציטוט MLAInternational, World Book Childcraft. Science Year: The World Book Science Annual. U.S.A, 1978.
אזהרה: ציטוטים אלה לעיתים לא מדויקים ב 100%.