Fig. 4From: Standardisation, calibration and correlation of the Kübler-index and the vitrinite/bituminite reflectance: an inter-laboratory and field related studyCorrelation between standards of Martin Frey and standards used by the technical petrology group at the TU Darmstadt (Table 1) to adapt the standard FWHM-values in ∆°2θ to Kübler-Index data measured in Basel (n = 12, r > 0.99). See text for regression equationBack to article page