BOZZON, ALESSANDRO, MARCO BRAMBILLA, STEFANO CERI, ANDREA MAURI, and RICCARDO VOLONTERIO. 2015. “DESIGNING COMPLEX CROWDSOURCING APPLICATIONS COVERING MULTIPLE PLATFORMS AND TASKS”. Journal of Web Engineering 14 (5-6):443-73. https://journals.riverpublishers.com/index.php/JWE/article/view/3847.