BUTERIN, S. On half inverse problem for differential pencils with the spectral parameter in boundary conditions. Tamkang Journal of Mathematics, [S. l.], v. 42, n. 3, p. 355–364, 2011. DOI: 10.5556/j.tkjm.42.2011.912. Disponível em: https://journals.math.tku.edu.tw/index.php/TKJM/article/view/912. Acesso em: 19 may. 2025.