DENEVA, S.; DIAMANDIEV, V. Problems, connected with controlled nonholonomic constraints. Ann. Sofia Univ. Fac. Math. and Inf., [S. l.], v. 84, p. 159–164, 1993. Disponível em: https://stipendii.uni-sofia.bg/index.php/fmi/article/view/477. Acesso em: 5 dec. 2024.