Hazin, Tarcísio, Dênis Leite, Pedro H. R. Macêdo, Daniel V. Pires, Alexandre M. A. Maciel, and Mêuser J. S. Valença. " Identification of bottlenecks in gamified e-learning and indication of the most frequent errors to enable and prioritize improvements." Proceedings of the 30th Brazilian Symposium on Computers in Education, Brasília/DF, 2019. SBC, 2019, pp.883-891.