KHRABUSTOVSKYI, V. Analogs of Generalized Resolvents for Relations Generated by a Pair of Differential Operator Expressions One of which Depends on Spectral Parameter in Nonlinear Manner. Журнал математичної фізики, аналізу, геометрії, Харків, Україна, v. 9, n. 4, p. 496–535, 2013. Disponível em: http://jmag.ilt.kharkiv.ua/index.php/jmag/article/view/jm09-0496e. Acesso em: 2 трав. 2024.