Langgulung, H. (1971). A cross-cultural study of the child's conception of situational causality in India, Western Samoa, Mexico, and the United States. University of Georgia.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Langgulung, Hasan. A Cross-cultural Study of the Child's Conception of Situational Causality in India, Western Samoa, Mexico, and the United States. Athens: University of Georgia, 1971.
توثيق جمعية اللغة المعاصرة MLA (الطبعة الثامنة)Langgulung, Hasan. A Cross-cultural Study of the Child's Conception of Situational Causality in India, Western Samoa, Mexico, and the United States. University of Georgia, 1971.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.