توثيق جمعية علم النفس الأمريكية APA (الطبعة السابعة)

Gassner, M. E. (2006). Investigating the long-term impact of adventure education: A retrospective study of Outward Bound Singapore's Classic 21-day Challenge course. University of Minnesota.

توثيق أسلوب شيكاغو (الطبعة السابعة عشر)

Gassner, Michael Erwin. Investigating the Long-term Impact of Adventure Education: A Retrospective Study of Outward Bound Singapore's Classic 21-day Challenge Course. Minnesota: University of Minnesota, 2006.

توثيق جمعية اللغة المعاصرة MLA (الطبعة الثامنة)

Gassner, Michael Erwin. Investigating the Long-term Impact of Adventure Education: A Retrospective Study of Outward Bound Singapore's Classic 21-day Challenge Course. University of Minnesota, 2006.