1. Gezondheidsraad. Avies inzake advieswaarden voor de kwaliteit van de buitenlucht (in Dutch). Verslagen adviezen rapporten, Dutch Ministry of public health and environment no. 40 (1977)
2. Methods used in establishing permissible levels in occupational exposure to harmful agents. Technical report series, no. 601, Geneva, WHO 1977
3. Methods used in the USSR for establishing biologically safe levels of toxic substances. Geneva: WHO 1975
4. Occupational exposure limits for airborne toxic substances. Occupational safety and Health Series 37, ILO, Geneva 1977
5. Threshold Limit Values for chemical substances and physical agents in the workroom environment. American Conference of Governmental Industrial Hygienists (ACGIH), Cincinnati 1977