1. International Agency for Research on Cancer. Monographs on the evaluation of the carcinogenic risk of chemicals to humans;49:,1990
2. World Health Organisation Regional Office for Europe. Air quality guidelines for Europe. WHO Regional Publications, European Series;(WHO Regional Publ, European Series,1988
3. Occupational Exposure Limits,1993
4. Biological and environmental aspects of chromium;Langird, S.,1982
5. The carcinogenicity of chromium and its salts;Norseth, T.;BrJ Ind Med,1986