Lk. Antanovskii et al., A NOTE ON A CAPILLARITY MODEL AND THE NONLINEAR SCHRODINGER-EQUATION, Journal of physics. A, mathematical and general, 30(16), 1997, pp. 555-557
A system of two equations governing the irrotational flow of a capilla
ry fluid is shown, for a particular class of free energy functions, to
reduce to a nonlinear Schrodinger equation.