Torres del Castillo, G. and Bernal Bautista, A. (2000) “Alternative Hamiltonians in classical mechanics and geometrical optics”, Revista Mexicana de Física, 46(6), pp. 551–555. Available at: https://rmf.smf.mx/ojs/index.php/rmf/article/view/3011 (Accessed: 5 July 2024).