Al Kunifed، A.، و Wوersee، J. (1993). INVESTIGATION OF HIGH SCHOOL CHEMISTRY STUDENTS' CONCEPTS OF CHEMICAL SYMBOL, FORMULA, AND EQUATION: STUDENTS' PRESCIENTIFIC CONCEPTIONS (رسالة دكتوراه غير منشورة). Louisiana State University، باتون روج. مسترجع من http://search.mandumah.com/Record/616930
Al Kunifed، Ali، و James Wوersee. "INVESTIGATION OF HIGH SCHOOL CHEMISTRY STUDENTS' CONCEPTS OF CHEMICAL SYMBOL, FORMULA, AND EQUATION: STUDENTS' PRESCIENTIFIC CONCEPTIONS" رسالة دكتوراه. Louisiana State University، باتون روج، 1993. مسترجع من http://search.mandumah.com/Record/616930