1. 9) American Conference of Governmental Industrial Hygienists . Threshold Limit Value for Chemical Substances and Physical Agents in the Workroom Envitonment with Intended Changes. (1978)
2. 10) WESTER U. A Simple Formulae approximation of the ACGIH Curve of Relative Spectral Effectiveness of Actinic UV, RI Internal Report. Dept. of Radiation Physics, Karolinska Institute. (1981) vol.10401,
3. 11) International Non-ionizing Radiation Committee of the International Radiation Protection Association . Proposed Change to the IRPA 1985 Guidelines on Limits of Exposure to Ultraviolet Radiation. Health Physics. (1989) vol. 56, no. 6, p. 971 - 972 .
4. 12) International Radiation Protection Association. Health Issues of Ultraviolet A Sunbeds Used for Cosmetic Purposes. Health Physics. (1991) vol.61, no.2, p.285-288.
5. 13) International Radiation Protection Association. IRPA Guidelines on Protection against Non-Ionizing Radiation. McGraw-Hill. (1991)