1. American National Standards Institute (ANSI), 2000a. A14-1: American national standard for ladders—portable wood—safety requirements, American Ladder Institute, Chicago.
2. American National Standards Institute (ANSI), 2000b. A14-2: American national standard for ladders—portable metal—safety requirements, American Ladder Institute, Chicago.
3. American National Standards Institute (ANSI), 2002. A14-3: American national standard for ladders—fixed—safety requirements, American Ladder Institute, Chicago.
4. Measures to prevent portable ladder accidents in the construction industry;Axelsson;Ergonomics,1995
5. Ladder injuries mechanisms, injuries and consequences;Björnstig;Journal of Safety Research,1992