“Asymptotics of a Generalized Solution of Linear Singularly Perturbed Systems of Higher Order Differential Equations With Degenerations in the Case of Multiple Spectrum of Boundary Coupling of Matrices”. 2014. Neliniini Kolyvannya 17 (3): 379-98. https://twinhead.imath.kiev.ua/index.php/nosc/article/view/751.