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2. American National Standards Institute (ANSI), National Electrical Manufacturers Association (NEMA), 2011. Criteria for safety symbols (ANSI Z535-3-2011). NEMA, Rosslyn, VA.
3. American National Standards Institute (ANSI), American Society of Safety Engineers (ASSE), 2009. Safety Requirements for Confined Spaces (ANSI/ASSE: Z117.1-2009). ANSI, Washington, D.C.
4. American National Standards Institute (ANSI), American Society of Safety Engineers (ASSE), 2011. Prevention Through Design: Guidelines for Addressing Occupational Hazards and Risks in Design and Redesign Processes (ANSI/ASSE: Z590.3-2011). ANSI, Washington, D.C.
5. Reducing the gap between procedures and practice lessons from a successful safety intervention;Antonsen;Saf. Sci. Monitor,2008