1. O.V. Pylypovskyi, V.P. Kravchuk, D.D. Sheka, D. Makarov, O.G. Schmidt, Y. Gaididei, Phys. Rev. Lett. 114, 197204 (2015)
2. A. Hubert, R. Schäfer, Magnetic Domains (Springer, Berlin, 1998)
3. W.F. Brown Jr., Micromagnetics (Interscience Publishers, New York, 1963)
4. G. Toulouse, M. Kléman, J. Phys. Lett. 37, L149 (1976)
5. M. Kléman, Points, Lines and Walls (Wiley, Chichester, 1983)