1. S.P. McGlynn, T. Azumi, M. Kinoshita, Molecular Spectroscopy of the Triplet State (Prentice Hall, Englewood Cliffs, 1969)
2. V.N. Parmon, A.I. Kokorin, G.M. Zhidomirov, Stable Biradicals (Nauka, Moscow (in Russian), 1980)
3. E.G. Rosantsev, Organic paramagnetics, in: Saratov StateUniv., ed. by E.G. Rosantsev, M.D. Gol’dfeyn, V.F. Pulin (Saratov, 2000) (in Russian)
4. M.D. Gol’dfeyn, E.G. Rosantsev, Free radicals and organic paramagnetics. Univ. Proc. Volga Region 1(5), 60–72 (2014). (in Russian)
5. E.V. Tretyakov, V.I. Ovcharenko, The chemistry of nitroxides in the molecular design of magnets. Russ. Chem. Rev. 78(11), 971–1012 (2009). https://doi.org/10.1070/RC2009v078n11ABEH004093