Multiplatform Environment Joining Digital TV, Mobile Devices and Traditional e-Learning with Collaborative Learning. - David Abadía-Gallego; Ángel Esteban Ballano; Jorge Vea-Murguía; Juan-José Navamuel-Castillo; Pablo Martín de la Hoz; Anselmo Navarro; Angel Lafuente (CSEDU (2), 2009)