Mohamed M. Mousa and  Aidarkhan Kaltayev,  Constructing Approximate and Exact Solutions for Boussinesq Equations using Homotopy Perturbation Padé Technique.   journal   = {International Journal of Mathematical and Computational Sciences}, [online]. World Academy of Science, Engineering and Technology.
    February 2009, vol. 26(2). 99 - 107
    [viewed 18 April 2021]. Available from: https://publications.waset.org/pdf/2011.