Anderson, R. L., Sukeyuki Kumei. and Wulfman, and C. E. (1972) “Invariants of the equations of wave mechanics I”, Revista Mexicana de Física, 21(1), pp. 1–33. Available at: https://rmf.smf.mx/ojs/index.php/rmf/article/view/998 (Accessed: 5 July 2024).