Dalrymple-Alford, I. J. (1979). A school-based study of the learning and understanding of ratio/ proportionality by pupils of average mathematical ability at 10+, 12-13 and 15-16.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Dalrymple-Alford, Ian James. A School-based Study of the Learning and Understanding of Ratio/ Proportionality by Pupils of Average Mathematical Ability at 10+, 12-13 and 15-16. 1979.
توثيق جمعية اللغة المعاصرة MLA (الطبعة الثامنة)Dalrymple-Alford, Ian James. A School-based Study of the Learning and Understanding of Ratio/ Proportionality by Pupils of Average Mathematical Ability at 10+, 12-13 and 15-16. 1979.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.