Gerber, R. V. (1979). Development of competence and performance in cartographic language by children at the concrete level of map-reasoning.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Gerber, Rodney Victor. Development of Competence and Performance in Cartographic Language by Children at the Concrete Level of Map-reasoning. 1979.
توثيق جمعية اللغة المعاصرة MLA (الطبعة الثامنة)Gerber, Rodney Victor. Development of Competence and Performance in Cartographic Language by Children at the Concrete Level of Map-reasoning. 1979.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.