4-Body Problem of Classical Electrodynamics - Derivation of Equations of Motion (I). Letters in Nonlinear Analysis and its Applications, [S. l.], v. 3, n. 1, p. 28–47, 2025. Disponível em: https://lettersinnonlinearanalysis.com/index.php/lnaa/article/view/51. Acesso em: 24 may. 2026.