MAK, D., and K. W. J. NG IP. “Intrinsic Motivation of University Students in Participating in Physical Fitness Training Programs: 大學生參加健身訓練課程的內發動機”. Asian Journal of Physical Education &Amp; Recreation, vol. 5, no. 2, Dec. 1999, pp. 31-34, doi:10.24112/ajper.51226.