MHD flow of micropolar and Williamson fluids over a bi-directional stretching sheetMuhammad Ramzan, Abdullah Dawar, Anwar Saeed, Poom Kumam and Wiboonsak WatthayuEur. Phys. J. Plus, 137 7 (2022) 869DOI: https://doi.org/10.1140/epjp/s13360-022-03071-1