1- Balaban A.T., Schroth W. and Fischer G. (1969). Pyrylium saltsAdvances in Heterocyclic Chem.,(ed. . Katritzky A.R and Balaban A.T.), Vol. 10, P.241-326, Academic Press.
2- Balaban A.T., Katritzky A.R and Sempie B.M. (1962). Tetrahedron, 18,4001.
3- Balaban A.T. (1968). Tetrahedron, 24, 5059.
4- Ibrahim N.F. (1974). Studies on the reaction of Pyrylium Salts. M.Sc thesis, Baghdad Univ. P. 9-27.
5- Al-Hadithei M.A.K. (2002). A Synthesis of some Hetrocyclic compounds and study ther Chem. Spec. Properties. M.Sc thesis, Al-anbar Univ. 22,45.
6- AL-Heety M.M. (2005). Comparative study of Charge transition complexes to DI- Pyryidinium Salts. Paper, pub. Al-Mustansiriyah Univ. Baghdad, Vol. 16, No.(3).
7- AL-Heety M.M. (2003). A Synthesis of some Pyrylium Salts and study reaction (Oxidation, Reaction with amines, Biological activity). MSc. thesis, University of Al-Anbar, 27-38.
8- Park C.S., Choi H.G., Lee H. and Lee W.K. (2000). Tetrahedron: Asymmetry. 11,3283.
9- G. Schatte, T. Chivers, C. Jaska and N. Sandblom, Chem. Commun., 1657 (2000).
10- A. J. Banister, I. Lavender, S. E. Lawrence, J. M. Rawson and W. Clegg,J. Chem. Soc., Chem. Commun., 29 (1994);
11- C. M. Aherne, A. J. Banister,I. Lavender, S. E. Lawrence and J. M. Rawson, Polyhedron, 15, 1877 (1996).
12- M. R. Bryce and A. Chesney, J. Chem. Soc., Chem. Commun., 195 (1995).
13- T. Chivers, M. Parvez and G. Schatte, Inorg. Chem., 40, 540 (2001).
14- A. J. Banister, I. Lavender, J. M. Rawson and R. J. Whitehead, J. Chem. Soc.,Dalton Trans., 1449 (1992).