Exact solution of the space-time fractional coupled EW and coupled MEW equations K. R. Raslan, Talaat S. EL-Danaf and Khalid K. Ali Eur. Phys. J. Plus, 132 7 (2017) 319 Published online: 21 July 2017 DOI: 10.1140/epjp/i2017-11590-9