1. Acceptable levels for breathing resistance of respiratory apparatus;Bentley;Archives of Environmental Health,1973
2. Contraintes et nuisances dans la vie de travail, enque̊te nationale de mars 1984 sur les conditions de travail;Bue,1986
3. On the minimum health and safety requirements for the use by workers of personal protection equipments at the workplace;CEE;Journal Officiel des Communautés Européennes,1989
4. European Committee for Standardization. prEN 140: Respiratory protective devices; Half-masks and quarter-mask; Requirements, testing, marking;CEN,1981
5. European Committee for Standardization. EN 140: Respiratory protective devices; Half-masks and quarter-mask; Requirements, testing, marking;CEN,1989