Yépez-Martínez, H., Porta, A. and Yépez, E. (2008) “n-order perturbative solution of the inhomogeneous wave equation”, Revista Mexicana de Física E, 54(2 Jul-Dec), pp. 168–174. Available at: https://rmf.smf.mx/ojs/index.php/rmf-e/article/view/4581 (Accessed: 23 December 2024).