G. Torres del Castillo, H. Cruz Domínguez, A. de Yta Hernández, J. Herrera Flores, and A. Sierra Martínez, “Mapping of solutions of the Hamilton--Jacobi equation by an arbitrary canonical transformation”, Rev. Mex. Fís., vol. 60, no. 4 Jul-Aug, pp. 301–0, Jan. 2014.