1. Polytechnic University of Madrid (UPM); Department of Mathematics; 3, Cardenal Cisneros, CP 28040 Madrid Spain
2. University of Valencia (UV); Astronomic Observatory; 2 Jose Beltran Street CP E-46980 Paterna, Valencia Spain
3. National University of Mexico (UNAM); Institute of Physics and Center for Complexity Sciences; Mexico City, Distrito Federal, CP 01000 Mexico Mexico
4. Queen Mary University of London; School of Mathematical Sciences; Mile End Road London E14NS UK