2013DIN EN 13906-2:2013-09 Cylindrical helical springs made from round wire and bar - Calculation and design - Part 2: Extension springs; German version EN 13906-2:2013
2013DIN EN 13906-2:2013 Cylindrical helical springs made from round wire and bar - Calculation and design - Part 2: Extension springs; German version EN 13906-2:2013
2002DIN EN 13906-2:2002 Cylindrical helical springs made from round wire and bar - Calculation and design - Part 2: Extension springs; German version EN 13906-2:2001