The effect of physical education goal orientations and enjoyment in adolescent physical activity: A parallel process latent growth analysis
Sport Exercise and Performance Psychology (2013) - Comment
doi: 10.1037/a0029806  issn: 2157-3913  issn: 2157-3905 

Sami Yli-Piipari, Vassilis Barkoukis, Timo Jaakkola, Jarmo Liukkonen