1. Lauterbur, P.C.: “NMR Spectra of Elements other than Hydrogen and Fluorine”, in: “Determination of Organic Substances by Physical Methods, Vol. 2” (Eds.: Nachod, F.C., Phillips, W.D.), New York: Academic Press, 1962, p. 511.
2. Scholl, R.L., Maciel, G.E., Musker, W.K.: J. Am Chem. Soc. 94 (1972) 6376.
3. Schraml, J., Pola, J., Jancke, H., Engelhardt, G., Cerny, M., Chvalovsky, V.: Collect. Czech. Chem. Commun. 41 (1976) 360.
4. Lippmaa, E., Maegi, M., Chvalovsky, V., Schraml, J.: Collect. Czech. Chem. Commun. 42 (1977) 318.
5. Schraml, J., Chvalovsky, V., Maegi, M., Lippmaa, E.: Collect. Czech. Chem. Commun. 42 (1977) 306.