Nonlinear sinusoidal and varicose instability in a boundary layer Litvinenko, Yu.A., Chernorai, V.G., Kozlov, V.V., Lofdahl, L., Grek, G.R., Chun, H.H. 2005 Doklady Physics 50 (3), 147–150, MAIK Nauka/Interperiodica Publishing Without Abstract   check pdf