Ram Naresh Shyam Sundar 0002 J. B. Shukla Modeling the removal of primary and secondary pollutants from the atmosphere of a city by rain. 282-295 2006 179 Appl. Math. Comput. 1 https://doi.org/10.1016/j.amc.2005.11.101 db/journals/amc/amc179.html#NareshSS06