Fig. 5From: Standardisation, calibration and correlation of the Kübler-index and the vitrinite/bituminite reflectance: an inter-laboratory and field related studyCorrelation between standards used by Martin Frey in Bern and in Basel to re-calculate the mm-values to KI ∆°2θ. The plot was re-drawn from an ink-painted graph by Martin Frey (n = 69, r = 0.97). See text for regression equationBack to article page