Accreditation and Quality Assurance, 13, 553-562. Springer New York Krysell, M, Becker, R, Buge, H G, Wegener, J W M, Benanou, D, Benali, D, Ringstad, O, Kvernheim, A L & Leslie, H A 2008, ' Certified reference materials for organic contaminants in sewage sludge-A feasibility study ', Accreditation and Quality Assurance, vol. 13, pp. 553-562 . https://doi.org/10.1007/s00769-008-0431-5