Lei, T., Wang, Z., Sun, Y., Shi, X., He, X. and Zhu, J. (2013) “Grey Relational Analysis for the Production of Dimethyl Ether Syngas in a Biomass Pyrolysis Reactor”, Journal of Technology Innovations in Renewable Energy, 2(1), pp. 53–59. doi: 10.6000/1929-6002.2013.02.01.7.