Authors
Sahar A. Aleid
Department of Mathematics, Universidad de Almería, Carretera Sacramento s/n, 04120, Almería, Spain
Mercè Mora
Department of Mathematics, Universitat Politècnica de Catalunya Jordi Girona, 1-3, 08034, Barcelona, Spain
María Luz Puertas
Department of Mathematics, Universidad de Almería, Carretera Sacramento s/n, 04120, Almería, Spain