1. Health effects of overexposure to respirable coal and silica dust // Best Practices for Dust Control in Coal Mining. Cincinnati, Ohio, National Institute for Occupational Safety and Health, 2010. p. 6 – 7. (на английски); WikiPDF (на руски)
1. Health effects of overexposure to respirable coal and silica dust // Best Practices for Dust Control in Coal Mining. Cincinnati, Ohio, National Institute for Occupational Safety and Health, 2010. p. 6 – 7. (на английски); WikiPDF (на руски)