1. Department of Mathematics; Centro Universitario de Plasencia, University of Extremadura, Avda; Virgen del Puerto 2 10600 Plasencia Spain
2. Department of NanoBiotechnology; Institute for Biophysics; BOKU - University of Natural Resources and Applied Life Sciences Vienna (BOKU); Muthgasse 11 1190 Vienna Austria
3. Biosurfaces Unit, CIC BiomaGUNE; Paseo Miramón 182 E-20009 San Sebastián-Donostia Spain
4. Department of Mathematics for Economics; Faculty of Economics; University of Valencia; 46022 Valencia Spain