\Bibitem{Muk79} \by N.~V.~Mukhina \paper Free laminar convection of a liquid in a ribbed slot \jour Prikl. Mekh. Tekh. Fiz. \yr 1979 \vol 20 \issue 4 \pages 42--46 \mathnet{http://mi.mathnet.ru/pmtf6349} \transl \jour J. Appl. Mech. Tech. Phys. \yr 1979 \vol 20 \issue 4 \pages 423--427 \crossref{https://doi.org/10.1007/BF00905591}