Phan, Nguyen Hong, and Nguyen Van Diep. “Generalized Diffusion Theory of Non-Rotational, Rigid Spherical Particle Sedimentation in Viscous Fluid”. <i>Vietnam Journal of Mechanics</i>, vol. 23, no. 3, Oct. 2001, pp. 159-66, doi:10.15625/0866-7136/9948.