NIKITIN, A. Exact solvability of PDM systems with extended Lie symmetries. Transactions of Institute of Mathematics, the NAS of Ukraine, [S. l.], v. 16, n. 1, p. 113–130, 2019. Disponível em: https://trim.imath.kiev.ua/index.php/trim/article/view/361. Acesso em: 20 jul. 2024.