1. W. Buchner , R.Schliebs, G.Winter and K. H.Buchel, in Industrial Inorganic Chemistry, VCH, Berlin, 1989, p. 523.
2. Catalysts, Kinetics and Reactor Design in Phthalic Anhydride Synthesis
3. Preface
4. I. Barin , Thermochemical Data of Pure Substances, Verlag Chemie, Berlin, 1989.