Mittal, A., and L.-F. Cheong. “Formulation and Use of Time-to-Collision in Content-Based Retrieval”. INFOCOMP Journal of Computer Science, vol. 6, no. 1, Mar. 2007, pp. 18-29, https://infocomp.dcc.ufla.br/index.php/infocomp/article/view/160.