1. Olin, H.B., Schmidt, J.L. and Lewis, W.H. 1995.Construction Principles, Materials, and Methods,, 6th ed., 101–114. New York: Van Nostrand Reinhold.
2. HEW (NIOSH) Pub. No. 75-120,1975
3. DHHS (NIOSH) Pub. No. 2000-105,1996
4. Surveillance of respirable crystalline silica dust using OSHA compliance data (1979-1995)