TRAILER Project (Tagging, Recognition, Acknowledgment of Informal Learning Experiences) A Methodology to Make Learners' Informal Learning Activities Visible to the Institutions. - Francisco J. García-Peñalvo; Miguel Ángel Conde González; Valentina Zangrando; Alicia García-Holgado; Anton M. Seoane; Marc Alier Forment; Nikolas Galanis; Francis Brouns; Hubert Vogten; David Griffiths; Aleksandra Mykowska; Gustavo Ribeiro Alves; et al. (J. Univers. Comput. Sci., 2013)