\Bibitem{Tri91} \by Yu.~Ya.~Trifonov \paper Stability of two-dimensional traveling waves on a vertically draining liquid film to three-dimensional perturbations \jour Prikl. Mekh. Tekh. Fiz. \yr 1991 \vol 32 \issue 2 \pages 72--77 \mathnet{http://mi.mathnet.ru/pmtf4222} \transl \jour J. Appl. Mech. Tech. Phys. \yr 1991 \vol 32 \issue 2 \pages 210--214 \crossref{https://doi.org/10.1007/BF00858037}