Lopez-Monsalvo, C.S., and A.C. Gutiérrez-Piñeres. “The Variational Bi-Complex Formulation of Maxwell’s Equations”. Revista de la Escuela de Física 6, no. 1 (June 22, 2018): 86–101. Accessed May 19, 2024. https://www.camjol.info/index.php/fisica/article/view/7031.