Yli-Piipari, S. (2011). The development of students ́ physical education motivation and physical activity: A 3.5-year longitudinal study across grades 6 to 9.
Chicago-viite (17. p.)Yli-Piipari, Sami. The Development of Students ́ Physical Education Motivation and Physical Activity: A 3.5-year Longitudinal Study Across Grades 6 to 9. Jyväskylä, 2011.
MLA-viite (9. p.)Yli-Piipari, Sami. The Development of Students ́ Physical Education Motivation and Physical Activity: A 3.5-year Longitudinal Study Across Grades 6 to 9. 2011.
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