Malak, M. A., & Nicholas, J. (1976). The relationship between certain piagetian tasks and arithmetic ability of the first grade Saudi male children. University of Northern Colorado, College of Education, Department of Curriculum and Instruction.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Malak, Mohammad Ali, و Joe Nicholas. The Relationship Between Certain Piagetian Tasks and Arithmetic Ability of the First Grade Saudi Male Children. Greeley: University of Northern Colorado, College of Education, Department of Curriculum and Instruction, 1976.
توثيق جمعية اللغة المعاصرة MLA (الطبعة الثامنة)Malak, Mohammad Ali, و Joe Nicholas. The Relationship Between Certain Piagetian Tasks and Arithmetic Ability of the First Grade Saudi Male Children. University of Northern Colorado, College of Education, Department of Curriculum and Instruction, 1976.