توثيق جمعية علم النفس الأمريكية APA (الطبعة السابعة)

Esmael Ahmed, Tsegay Girmay, & Longdom Publishing. Psychoactive Substances Use (Khat, Alcohol and Tobacco) and Associated Factors among Debre Markos University Students, North-West Ethiopia, 2013.

توثيق أسلوب شيكاغو (الطبعة السابعة عشر)

Esmael Ahmed, Tsegay Girmay, و Longdom Publishing. Psychoactive Substances Use (Khat, Alcohol and Tobacco) and Associated Factors Among Debre Markos University Students, North-West Ethiopia, 2013.

توثيق جمعية اللغة المعاصرة MLA (الإصدار التاسع)

Esmael Ahmed, et al. Psychoactive Substances Use (Khat, Alcohol and Tobacco) and Associated Factors Among Debre Markos University Students, North-West Ethiopia, 2013.