1. A. Z. Patashinskii and V. L. Pokrovskii, Fluctuation Theory of Phase Transitions (Nauka, Moscow, 1982; Pergamon, Oxford, 1979).
2. V. V. Prudnikov, P. V. Prudnikov, and A. N. Vakilov, Description of Non-Equilibrium Critical Behaviour in Disordered Systems by Theoretical Methods (Fizmatlit, Moscow, 2013) [in Russian].
3. V. L. Berezinskii, Sov. Phys. JETP 32, 493 (1970).
4. V. L. Berezinskii, Low Temperature Properties of Two-Dimensional Systems (Fizmatlit, Moscow, 2007) [in Russian].
5. J. M. Kosterlitz and D. J. Thouless, J. Phys. C 6, 1181 (1973).