\Bibitem{Nik95} \by V.~V.~Nikulin \paper Motion of a swirled fluid in the core of a vertical, tornado-like vortex \jour Prikl. Mekh. Tekh. Fiz. \yr 1995 \vol 36 \issue 2 \pages 81--87 \mathnet{http://mi.mathnet.ru/pmtf3643} \elib{https://elibrary.ru/item.asp?id=35240189} \transl \jour J. Appl. Mech. Tech. Phys. \yr 1995 \vol 36 \issue 2 \pages 220--225 \crossref{https://doi.org/10.1007/BF02369652}