Tondello, G. F. , Kappen, D. L. , Mekler, E. D. , Ganaba, M. , & Nacke, L. E. . (2016). Heuristic Evaluation for Gameful Design. In Proceedings of the 2016 Annual Symposium on Computer-Human Interaction in Play Companion Extended Abstracts (pp. 315–323). ACM. doi:10.1145/2968120.2987729