1. American National Standard Specification for Accident Prevention Signs;American National Standards Institute;ANSI Z35.1.,1972
2. Safety Color Code;American National Standards Institute;ANSI Z535.1,1987
3. Environmental and Facility Safety Signs;American National Standards Institute;ANSI Z535.2,1987
4. Criteria for Safety Symbols;American National Standards Institute;ANSi Z535.3,1987