1. UNI EN 81-1, Safety Rules for the Construction and Installation of Lifts – Electric Lift, third ed., March 1999.
2. Testing of lift car progressive safety gears;Mellor;Elevatori.,2005
3. The natural behaviour of elevator safety gears and triggering devices;De Jong;Elevatori.,2005
4. Friction in progressive safety gears;Mellor;Elevatori.,2004
5. 95/16/EC European Parliament and Council Directive of 29 June 1995 on the approximation of the laws of the Member States relating to lifts.