1. GD 1146/2006 concerning the minimum safety and health requirements for the use of work equipment by workers at work, on line at: https://osha.europa.eu/fop/romania/ro/legislation/hotarare_1146_30_august_2006.shtml
2. SR EN 131-1:2016 Ladders - Part 1: Terms, types, functional sizes
3. SR EN 61478:2003/A1:2004, Live working - Ladders of insulating material (2004)
4. Radu S.M., Pasculescu V.M., Safety level assessment in potentially explosive atmospheres - Recent Advances in Industrial and Manufacturing Technologies, 98-103 (2013)