Mahendra A. Patel, and N. B. Desai. “An Approximate Analytical Solution of Boussinesq’s Equation for Infiltration Phenomenon in Unsaturated Porous Medium”. International Journal of Mathematics And Its Applications, vol. 6, no. 1 - C, Feb. 2018, pp. 463-70, https://ijmaa.in/index.php/ijmaa/article/view/1090.