Application of the modern trend of fractional differentiation to the MHD flow of a generalized Casson fluid in a microchannel: Modelling and solution⋆Ilyas Khan, Muhammad Saqib and Farhad AliEur. Phys. J. Plus, 133 7 (2018) 262DOI: https://doi.org/10.1140/epjp/i2018-11899-9