1. M.A. Lavrent’ev, “On the theory of conformal mappings,” Tr. Fiz.-Mat. Inst. Akad. Nauk SSSR, 5, 159–245 (1934).
2. G.M. Goluzin, Geometric theory of functions of a complex variable. Nauka, Moscow, 1966.
3. G.P. Bakhtina, Variational methods and quadratic differentials in problems for disjoint domains. PhD thesis, Kiev, 1975.
4. A.K. Bakhtin, G.P. Bakhtina, and Yu.B. Zelinskii, Topological-algebraic structures and geometric methods in complex analysis. Inst. Math. NAS Ukraine, Kiev, 2008.
5. V.N. Dubinin, “Separating transformation of domains and problems of extremal division,” Zap. Nauchn. Sem. Leningrad. Otdel. Mat. Inst. Ros. Akad. Nauk., 168, 48–66 (1988).