[1] CMUC, Department of Mathematics, University of Coimbra, 3001 - 454 Coimbra, Portugal
[2] Department of Physics and Mathematics, ISEC, Quinta da Nora, Rua Pedro Nunes, 3030-199 Coimbra, Portugal
[3] Department of Chemical Engineering, Rua Sílvio Lima, Pólo II, 3030-790 Coimbra, Portugal
[4] Department of Ophthalmology, Faculty of Medicine, University of Coimbra, 3001 - 454 Coimbra, Portugal