Asymptotic formulations of the eigenvalues and eigenfunctions for a   boundary value problem
  In this work a discontinuous boundary-value problem with retarded argument which contains spectral parameter in the transmission conditions at the point of discontinuity are investigated. We obtained asymptotic formulas for the eigenvalues and eigenfunctions. 
Erdo\u{g}an \c{S}en, Azad Bayramov
math.CA math.SP