1. Free-to-play games: Professionals' perspectives;Alha;DiGRA Nordic’14: Proceedings of the 2014 International DiGRA Nordic Conference,2014
2. Diagnostic and statistical manual of mental disorders [DSM-5],2013
3. Playing and paying on the Internet: Adoption determinants for Spanish gamers;Barbera;Journal of International Business Research,2006
4. The business of micro transactions? What is the players' motivation for purchasing virtual items?;van Berlo,2016