1. Spanish Association of Standardization and Certification (AENOR) . Management Systems Quality. Fundamentals and vocabulary [in Spanish]. UNE-EN ISO 9000:2000. Madrid: AENOR; 2000.
2. Spanish Association of Standardization and Certification (AENOR) . Clinical Laboratories. Particulars requirements for quality and competence. UNE-EN ISO 15189 [in Spanish]. Madrid: AENOR; 2003.
3. Spanish Society of Clinical Chemistry and Molecular Pathology (SEQC) . Committee for Quality Assurance and Accreditation of Laboratory SEQC. Analytical Quality Commission. Selection and Evaluation of Analytical Systems [in Spanish]. 1994. B-35827.
4. Spanish Society of Clinical Chemistry and Molecular Pathology (SEQC) . Committee for Quality Assurance and Accreditation of Laboratory. Analytical Quality Commission Components of biological variability for desirable analytical quality specifications databases of biological variability (annex 1) [in Spanish]. Available at http://www.seqc.es/es/Comisiones/7/51/102/Base_de_datos_de_Variacion_biologica_%7C_Bases_de_datos_y_documentos_del_Comite_de_Garantia_de_la_Calidad_y_Acreditacion_%7C_Comite_de_Garantia_de_la_Calidad_y_Ac. Accessed December 20, 2012.
5. Product information for the Radiometer ABL-90 FLEX gas analyzer. Available at http://www.radiometer.co.uk/en-gb/products/blood-gas/abl90-flex-analyzer. Accessed December 20, 2012.