@article {mendez2001prvir, title = {Prvir: An integration between an intelligent tutoring system and a virtual environment}, journal = {SCI2001}, volume = {8}, year = {2001}, pages = {175{\textendash}180}, attachments = {http://nil.fdi.ucm.es/sites/default/files/P000954.pdf}, author = {Gonzalo M{\'e}ndez and Ang{\'e}lica de Antonio and Herrero, Pilar} }