Agnihotri, R., N. Agnihotri, Raj Kamal, and Jaswant R. Mehta. “3-Hydroxy-2-(3´-Methyl-2&Acute;-Thienyl)-4-Oxo-4H-1-Benzopyran As an Analytical Reagent for the Spectrophotometric Determination of Tungsten(VI)”. Asian Journal of Chemistry 20, no. 6 (March 30, 2010): 4469–4476. Accessed November 29, 2024. https://asianpubs.org/index.php/ajchem/article/view/19046.