UNE-EN ISO 20623:2004 Petroleum and related products - Determination of the extreme-pressure and anti-wear properties of fluids - Four ball method (European conditions) (ISO 20623:2003)
2018UNE-EN ISO 20623:2018 Petroleum and related products - Determination of the extreme-pressure and anti-wear properties of lubricants - Four-ball method (European conditions) (ISO 20623:2017)
2004UNE-EN ISO 20623:2004 Petroleum and related products - Determination of the extreme-pressure and anti-wear properties of fluids - Four ball method (European conditions) (ISO 20623:2003)