Motesaddi Zarandi, Saeed, et al. “Investigating the Efficiency of Biological Filters for Ammonia Removal”. Irtiqa Imini Pishgiri Masdumiyat (Safety Promotion and Injury Prevention), vol. 1, no. 2, Sept. 2013, pp. 63-68, doi:10.22037/meipm.v1i2.4972.