1. Cyclic β-Diketones, Ed. by G. Ya. Vanag (Izd-vo AN LatvSSR, Riga, 1961) [in Russian].
2. A. J. Birch, J. Chem. Soc., 3026 (1951).
3. M. N. Makanova and V. P. Oshkaya, Izv. Akad. Nauk. Latv. SSR, No. 5, 113 (1954).
4. A. A. Apsit, K. Ya. Dorfman, and V. P. Oshkaya, Zh. Neorg. Khim. 19(1), 182 (1974).
5. B. A. Spicer, J. W. Ross, and H. Smith, Clin. Exp. Immunol. 21(3), 419 (1975).