On the Boundary Value Problem with the Operator in Boundary Conditions   for the Operator-Differential Equation of the Third Order
  In this paper the boundary value problem for one class of the operator-differential equations of the third order on a semi-axis, where one of the boundary conditions is perturbed by some linear operator is researched. There are received sufficient conditions on the operator coefficients of the considered boundary value problem, providing its correct and univalent resolvability in Sobolev type space. 
Araz R. Aliev, Sevindj F. Babayeva
math.FA