D. Sülzle, M. Verhoeven, J. K. Terlouw, H. Schwarz (1988). "Generation and Characterization of Sulfurous Acid (H2SO3) and of Its Radical Cation as Stable Species in the Gas Phase". Angew. Chem. Int. Ed. Engl.27: 1533–4. doi:10.1002/anie.198815331.Pemeliharaan CS1: Banyak nama: authors list (link)