author="Bellettini, Carlo and Lonati, Violetta and Malchiodi, Dario and Monga, Mattia and Morpurgo, Anna and Torelli, Mauro",
    title="How Challenging are Bebras Tasks? An IRT analysis based on the performance of Italian students",
    booktitle="ITiCSE '15 Proceedings of the 2015 ACM Conference on Innovation and Technology in Computer Science Education",
    address="New York",