1. S. V. Alekseenko, P. A. Kuibin, and V. L. Okulov, An Introduction to the Theory of Concentrated Vortices [in Russian], Institute of Thermophysics, Siberian Branch, Russ. Acad. Sci., Novosibirsk (2003).
2. V. A. Bogomolov, “Vorticity dynamics on a sphere,” Izv. Akad. Nauk SSSR, Mekh. Zhidk. Gaza, No. 6, 57–65 (1977).
3. A. V. Borisov and I. S. Mamaev, Mathematical Methods of the Dynamics of Vortex Structures [in Russian], Inst. Comput. Res., Moscow (2005).
4. A. V. Borisov, L. A. Gazizullina, and S. M. Ramodanov, “The thesis by E. Zermelo on the vortex hydrodynamics on a sphere,” Nelin. Dyn., 4, 497–513 (2008).
5. O. F. Vasil’ev, “On one forgotten work by I. S. Gromeka,” Prikl. Mat. Mekh., 15, 261–263 (1951).