Al-Dokheal, I. A., & Wolfe, E. V. (1983). The relationship between mathematics problem solving ability and Piagetian level of cognitive development in sixth grade male, Saudi Arabian pupils. University of Northern Colorado, College of Education, Department of Elementary Education and Reading.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Al-Dokheal, Ibrahim Ali, و Elaine V. Wolfe. The Relationship Between Mathematics Problem Solving Ability and Piagetian Level of Cognitive Development in Sixth Grade Male, Saudi Arabian Pupils. Colorado: University of Northern Colorado, College of Education, Department of Elementary Education and Reading, 1983.
توثيق جمعية اللغة المعاصرة MLA (الطبعة الثامنة)Al-Dokheal, Ibrahim Ali, و Elaine V. Wolfe. The Relationship Between Mathematics Problem Solving Ability and Piagetian Level of Cognitive Development in Sixth Grade Male, Saudi Arabian Pupils. University of Northern Colorado, College of Education, Department of Elementary Education and Reading, 1983.