توثيق جمعية علم النفس الأمريكية APA (الطبعة السابعة)

Clapp, F. L., & Huebner, B. P. (1924). The number combinations, their relative difficulty and the frequency of their appearance in text-books.

توثيق أسلوب شيكاغو (الطبعة السابعة عشر)

Clapp, Frank L., و Bernard P. Huebner. The Number Combinations, Their Relative Difficulty and the Frequency of Their Appearance in Text-books. Madison, Wis, 1924.

توثيق جمعية اللغة المعاصرة MLA (الطبعة الثامنة)

Clapp, Frank L., و Bernard P. Huebner. The Number Combinations, Their Relative Difficulty and the Frequency of Their Appearance in Text-books. 1924.