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
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