1. Alvarez-Alduan, F., Capdevila, C, Roca, M.: XVI. CSI, Heidelberg, 259 (1972)
2. Boumans, P. W. J. M.: Theory of spectrochemical excitation. London: Hilger � Watts 1966
3. Corliss, C. H., Bozman, W. R.: NBS-Monograph 53 (1962)
4. Leushacke, D. F., Nickel, H.: Spectrochim. Acta, 26B, 391, 409 (1971)
5. Nickel, H., Schaeps, R.: XVII. CSI, Florenz, 16 (1973)