Alcanzare, M. and Esguerra, J.P. 2010. Persistent 2D random walk with geometrically shrinking steps with four directions. Proceedings of the Samahang Pisika ng Pilipinas, 28(1), SPP-2010-6A-02. URL: https://proceedings.spp-online.org/article/view/SPP-2010-6A-02.