\Bibitem{ZhiKolShe82} \by E.~F.~Zhigalko, L.~L.~Kolyshkina, V.~D.~Shevtsov \paper Vortical singularity of self-similar gas flow in the reflection of a shock wave \jour Prikl. Mekh. Tekh. Fiz. \yr 1982 \vol 23 \issue 1 \pages 107--111 \mathnet{http://mi.mathnet.ru/pmtf5782} \transl \jour J. Appl. Mech. Tech. Phys. \yr 1982 \vol 23 \issue 1 \pages 99--103 \crossref{https://doi.org/10.1007/BF00911986}