Angel Garrido
National University of Distance Education, Madrid
Spain

Angel Garrido
Department of Fundamental Mathematics, Faculty of Sciences, National University of Distance
Education, Madrid, Spain, Paseo Senda del Rey, 9, 28040, Madrid, Spain
E-mail: agarrido@mat.uned.es

Piedad Yuste
National University of Distance Education, Madrid
Spain

Piedad Yuste
Department of Philosophy, Faculty of Philosophy, National University of Distance Education,
Madrid, Spain, Paseo Senda del Rey, 7, 28040, Madrid, Spain
E-mail: pyuste@fsof.uned.es