homepages/22/4542,
Beatriz Pérez and Beatriz Pérez Valle, Home Page, https://scholar.google.es/citations?user=fAHEoEAAAAAJ, Universidad de La Rioja, Spain
homepages/51/2193,
Hong Tat Ewe and Hong-Tat Ewe, Home Page, http://staff.utar.edu.my/eweht/, Tunku Abdul Rahman University, Sungai Long, Malaysia / Multimedia University, Cyberjaya, Malaysia