1. Moskalyk R R. Gallium: The backbone of the electronics industry. Miner Eng, 2003, 16: 921–929
2. Luo T Y, Dai X D, Zhu D, et al. Mineralization of gallium: implication to Emeishan large igneous province (in Chinese). Acta Mineral Sin, 2007, 27: 281–286
3. Holl R, Kling M, Schroll E. Metallogenesis of germanium-A review. Ore Geol Rev, 2007, 30: 145–180
4. Ren D Y, Zhao F H, Dai S F, et al. Geochemistry of Trace Elements in Coal (in Chinese). Beijing: Science Press, 2006. 191–196
5. Tang X Y, Huang W H. Trace Elements in Chinese Coals (in Chinese). Beijing: The Commercial Press, 2004. 93–98