Keyvan Molanorouzi and  Selina Khoo and  Tony Morris,  The Relationship between Motivation for Physical Activity and Level of Physical Activity over Time.   journal   = {International Journal of Sport and Health Sciences}, [online]. World Academy of Science, Engineering and Technology.
    June 2015, vol. 104(8). 609 - 612
    [viewed 02 May 2024]. Available from: https://publications.waset.org/pdf/10001788.