Rana Khalid Naeem and  Asif Mansoor and  Waseem Ahmed Khan and  Aurangzaib,  Exact Solutions of Steady Plane Flows of an Incompressible Fluid of Variable Viscosity Using (ξ, ψ)- Or (η, ψ)- Coordinates.   journal   = {International Journal of Mathematical and Computational Sciences}, [online]. World Academy of Science, Engineering and Technology.
    November 2009, vol. 35(11). 996 - 1003
    [viewed 17 October 2021]. Available from: https://publications.waset.org/pdf/1733.