1. H. Schiff, Justus Lieb. Ann. Der. Chem. 131, 118 (1864)
2. B. Pedras, L. Fernandes, E. Oliveira, L. Rodríguez, M. Manuela, M. Raposo, J.L. Capelo, C. Lodeiro, Inorg. Chem. Commun. 12, 79 (2009)
3. L. Mishra, S.K. Dubey, Spectrochim. Acta Part A 68, 364 (2007)
4. K. Bhat, K.J. Chang, M.D. Aggarwal, W.S. Wang, B.G. Penn, D.O. Frazier, Mater. Chem. Phys. 44, 261 (1996)
5. I. Finar, vol 2. Organic Chemistry, 5thed, Longman, London, (1973).