Surface active agents - Colorimetric characterization of optically clear coloured liquids (products) as X, Y, Z tristimulus values in transmission; German version EN 1557:1996— 7 стр.
Clear liquids - Estimation of colour by the platinum-cobalt scale - Part 2: Spectrophotometric method (ISO 6271-2:2004); German version EN ISO 6271-2:2004— 9 стр.