Samson, A. (2014). Sources of self-efficacy during marathon training: A qualified, longitudinal investigation. The sport psychologist, 28(2), S. 164-175. doi:10.1123/tsp.2013-0027

Samson, Ashley. "Sources of Self-efficacy During Marathon Training: A Qualified, Longitudinal Investigation." The Sport Psychologist 28, no. 2 (2014): S. 164-175.

Samson, Ashley. "Sources of Self-efficacy During Marathon Training: A Qualified, Longitudinal Investigation." The Sport Psychologist 28.2 (2014): S. 164-175.