Aziz, Roslizawati Che, et al. “Student Motivation in Outdoor Recreation Engagement: Examining the Validity and Reliability of the Measuring Instruments”. The Journal of Contemporary Issues in Business and Government, vol. 27, no. 2, Apr. 2021, pp. 4723-31, https://www.cibgp.com/index.php/1323-6903/article/view/1388.