Fidayana, Ristia, 		Wirawan, Teguh, AND 		Panggabean, Aman.
" VALIDATION OF ION SELECTIVE ELECTRONIC METHODS AT PUPUK KALIMANTAN TIMUR COMPANY FOR DETERMINING AMMONIA LEVELS (NH3) IN AMBIENT AIR" <em>JURNAL KIMIA MULAWARMAN</em> [Online], Volume 19 Number 1 (30 November 2021)