1. Baron, L. J. (1993). The psychological effects of introducing tai chi as an alternative physical activity for young children. In S. Serpa, J. Alves, V. Ferreira & A. Paula-Brito (Eds.),Proceedings VIII World Congress of Sport Psychology(524-527). Lissabon: International Society of Sport Psychology.
2. Bottenburg, van M. (1994).Verborgen competitie. Over de uiteenlopende populariteit van sporten. Amsterdam: Bert Bakker.
3. Bottenburg, van M., Rijnen, B. & Sterkenburg, van J. (2005).Sports participation in the European Union. Trends and differences. Hertogenbosch – Niewegein: W.J.H. Mulier Institute – Arko Sports Media.
4. Burke, M. (1998). Is boxing violent? Let’s ask some boxers. In D. Hemphill (Ed.),All part of the game. Violence and Australian sport(111-132). Melbourne: Walla Walla Press.
5. Caine, J. C. (1989). The effects of three operant instructional methods on skill level, selfefficacy and performance anxiety, with a complex motor task (Doctoral dissertation, California School of Professional Psychology, San Diego, 1987).Dissertation Abstracts International, 49(07), 1735.