Quested, E., Ntoumanis, N., Thøgersen-Ntoumani, C., Hagger, M. S., & Hancox, J. E. (2017). Evaluating quality of implementation in physical activity interventions based on theories of motivation: current challenges and future directions. International Review of Sport and Exercise Psychology, 10(1), 252-269. https://doi.org/10.1080/1750984x.2016.1217342