1. Y. ZHANG, J. BILLIET, R. DAMS, Staub Reinhalt. Luft, 41 (1981) 381.
2. Y. ZHANG, J. BILLIET, M. NAGELS, R. DAMS, Science Total Environm., 30 (1983) 167.
3. Y. ZHANG, J. BILLIET, R. DAMS, Science Total Environm., 41 (1985) 13.
4. Y. ZHANG, Samplign and Analysis of Particulate Matter suspended in the Workplace of an Iron Foundry, Ph. D. Thesis, University of Ghent, Belgium, 1984.
5. ACGHI, Threshold Limit Values for Chemical Substances and Physical Agents in the Workroom Environment with Intended Changes, Ohio, 1974.