Gustavo Steinmetz, Luís Eich, Gustavo Schroeder, Rosemary Francisco, and Jorge Barbosa. 2022.
 XPCodeHub: A gamified system model for learning programming through knowledge trails. In <em>Proceedings of the 33rd Brazilian Symposium on Computers in Education</em>, November 16, 2022, Manaus, Brasil. SBC, Porto Alegre, Brasil, 1367-1378. DOI: <a href="https://doi.org/10.5753/sbie.2022.225084">https://doi.org/10.5753/sbie.2022.225084</a>.