- Calibrating and Testing Direct-Reading Portable Gas Monitors. OSHA Safety and Health Information Bulletin (SHIB), (September 30, 2013). Provides workers and employers guidance on calibrating and testing direct-reading portable gas monitors (hereafter, "DRPGMs" or "instruments").
- Small Business Handbook (PDF). OSHA Publication 2209, (2005). Contains basic information about occupational safety and health, with specific focus on the needs of small business.
- Confined Spaces. National Ag Safety Database (NASD). Provides a linked reference to several videos relating to confined space entry.
- ANSI Z117.1 Committee. American Society of Safety Engineers (ASSE).
- NFPA 350: Guide for Safe Confined Space Entry and Work. National Fire Protection Association.