BORNFELD, B.; RAFAELI, S. Gamifying with badges: A big data natural experiment on Stack Exchange. First Monday, [S. l.], v. 22, n. 6, 2017. DOI: 10.5210/fm.v22i6.7299. Disponível em: https://journals.uic.edu/ojs/index.php/fm/article/view/7299. Acesso em: 26 oct. 2021.