1. Department of Mathematics, Mathematical Oncology Laboratory (MôLAB), University of Castilla-La Mancha, 13071 Ciudad Real, Spain
2. Department of Mathematics, University of Cádiz, 11510 Puerto Real, Cádiz, Spain
3. UGC Primary Care San Roque, Campo de Gibraltar, Cádiz, Spain
4. UGC Internal Medicine, University Hospital of Jerez and Department of Medicine, University of Cádiz, Cádiz, Spain