1. Germanium and germanium compounds;Adams,1992
2. Arroyo, F., Fernández-Pereira, C., Querol, X., Font, O., Coca, P., Chimenos, J.M., Fernández, A.I., 2008. Method for the recovery of germanium present in coal ash. Patent WO/2008/003808.
3. Mineral Commodity Profiles;Butterman,2005
4. Coal quality characters and metamorphic pattern in Wumuchang Area, Yimin;Chen;Coal Geol. China,2005
5. Quantitative interpretation of X-ray diffraction patterns of mixtures: I. Matrix flushing method for quantitative multicomponent analysis;Chung;J. Appl. Crystallogr.,1974