Puyda, D. V. “On Inverse Spectral Problems for Self-Adjoint Dirac Operators With General Boundary Conditions”. Methods of Functional Analysis and Topology 19, no. 4 (December 25, 2013): 346–363. Accessed February 4, 2026. https://zen.imath.kiev.ua/index.php/mfat/article/view/558.