“?SPECTROPHOTOMETRIC DETERMINATION OF TITANIUM AND IRON-ApPLICATION TO CHERAT VOLCANIC ASH, N.W.F.P”. Biological Sciences - PJSIR 41, no. 4 (August 24, 1998): 217–220. Accessed March 10, 2026. https://www.v2.pjsir.org/index.php/biological-sciences/article/view/2274.