Mohamed M. Mousa and  Aidarkhan Kaltayev Shahwar F. Ragab,  Investigation of a Transition from Steady Convection to Chaos in Porous Media Using Piecewise Variational Iteration Method.   journal   = {International Journal of Mathematical and Computational Sciences}, [online]. World Academy of Science, Engineering and Technology.
    October 2009, vol. 34(10). 869 - 878
    [viewed 24 October 2021]. Available from: https://publications.waset.org/pdf/6226.