1. U.G.C. Health Centre “Molino de la Vega,” Huelva, Spain.
2. U.G.C. Hematology, Hospital “Juan Ramón Jiménez,” Huelva, Spain.
3. Nursing Department, University of Huelva, Huelva, Spain.
4. Andalusian Public Health System Virtual Library, Hospital “Juan Ramón Jiménez,” Huelva, Spain.