1. The Sadtler Standard Spectra: Carbon-13 NMR Spectra, Sadtler Research Laboratories, Philadelphia, Vol. 3, No. 425 C (1976);
2. Vol. 43, No. 8463C (1980);
3. Vol. 63, No. 12476C (1982).
4. J. M. Briggs and E. W. Randal, J. Chem. Soc., Perkin Trans., 2, 1789 (1973).
5. A. I. Rezvukhin, G. G. Furin, G. A. Kalabin, et al., Izv. Sib. Otd. Akad. Nauk SSSR, Ser. Khim. Nauk, Issue 5, No. 9, (1982).