BS EN 60721-3-4:1993 Classification of environmental conditions. Classification of groups of environmental parameters and their severities-Stationary use at non-weatherprotected locations
1995BS EN 60721-3-4:1995 Clasificación de condiciones ambientales - Clasificación de grupos de parámetros ambientales y sus severidades - Uso estacionario en lugares no protegidos contra la intemperie
1991BS EN 60721-3-4:1993 Classification of environmental conditions. Classification of groups of environmental parameters and their severities-Stationary use at non-weatherprotected locations