DIN 22020-5:2005-02
硬煤开采原材料的研究 硬煤、焦炭和煤球的显微镜检查 第5部分:镜质体的反射率测量
Investigations of the raw material in hard-coal-mining - Microscopical examinations of hard coal, coke and briquettes - Part 5: Reflectance measurements on vitrinites / Note: DIN 22020-5 (1986-09) remains valid alongside this standard until 2005-07-31.