1. M. I. Portenko, Diffusion processes in media with membranes, (in Ukrainian), Proceedings of the Institute of Mathematics of the National Academy of Sciences of Ukraine (1995).
2. B. I. Kopytko, M. I. Portenko, The problem of pasting together two diffusion processes and classical potentials, Theory Stoch. Proc., 15, № 2, 126–139 (2009).
3. W. Feller, The parabolic differential equations and the associated semi-groups of transformations, Ann. Math., 55, 468–519 (1952); DOI: 10.2307/1969644.
4. A. D. Wentzell, Semigroups of operators that correspond to a generalized differential operator of second order(in Russian), Dokl. Akad. Nauk SSSR, 111, № 2, 269–272 (1956).
5. H. Langer, W. Schenk, Knotting of one-dimensional Feller processes, Math. Nachr., 113, 151–161 (1983); DOI: 10.1002/mana.19831130115.