Trace elements in human serum
 EC Directive 80/1107/EEC on the protection of workers from the risks related to exposure to chemical, biological and physical agents at work.
 EC Directive 98/24/EC on the protection of the health and safety of workers from the risks related to chemical agents at work.
 EC Directive 91/322/EEC on establishment of recommended threshold limit values for implementation of Council Directive 80/1107/EEC on the protection of workers from risks related to exposure to chemical, physical and biological agents at work.
 M. Wagner, C.L. Klein, H. Kleinert, C. Euchenhofer, U. Förstermann, C.J. Kirkpatrick. Pathobiology 65 (1997), 241-252.
 C.L. Klein, H. Köhler, C.J. Kirkpatrick. Pathobiology 62 (1994), 90-98.
 American Conference of Governmental Industrial Hygienists, Threshold limit values and biological exposure indices for 1994-1995, Cincinnati USA, 55-70
 Deutsche Forschungsgemeinschaft. List of MAK and BAT values, VCH, Weinheim (1994)
 European Commission, Guidelines for the production and certification of BCR reference materials Doc. BCR/48/93, Brussels 1994
 ISO-IEC-BIPM-IFCC-IUPAC-IUPAP-OIML. Guide to the Expression of Uncertainties in Measurement (GUM), Geneva, Switzerland (ISBN 92-67-10188-9).
 A.M.H. van der Veen, T.P.J. Linsinger, H. Schimmel, A. Lamberty, J. Pauwels. Accreditation and Quality Assurance 6 (2001), 290-294.
 T.P.J. Linsinger, J. Pauwels, A.M.H. van der Veen, H. Schimmel, A. Lamberty. Accreditation and Quality Assurance 6 (2001), 20-25.
 ISO Guide 33. Uses of Certified Reference Materials, International Organization for Standardization, Geneva 1989.