Amirov, R. K., Keskin, B., & Özkan, G. (2009). Direct and inverse problems for the Dirac operator with a spectral parameter linearly contained in a boundary condition. Ukrains’kyi Matematychnyi Zhurnal, 61(9), 1155-1166. https://umj.imath.kiev.ua/index.php/umj/article/view/3088