Srivastava, K.P., and A. Kumar. “UV Spectral Studies in Protonation of Cu-Phthalocyanine and Phthalocyanine in Sulphuric Acid-Solvent”. Asian Journal of Chemistry 13, no. 4 (March 30, 2010): 1539–1543. Accessed November 5, 2024. https://asianpubs.org/index.php/ajchem/article/view/22838.