A TENSORIAL FORM OF LAGRANGE’S EQUATIONS. Annual of Sofia University St. Kliment Ohridski. Faculty of Mathematics and Informatics, [S. l.], v. 82, n. 2, p. 249–286, 1991. Disponível em: https://annual.uni-sofia.bg/index.php/fmi/article/view/546. Acesso em: 4 feb. 2026.