Dym H., Arov D.Z. Bitangential direct and inverse problems for systems of integral and differential equations

Cambridge: Cambridge University Press, 2012. — 488 p.Canonical systems and related differential equations
Matrix valued functions in the Nevanlinna class
Interpolation problems, resolvent matrices and de Branges spaces
Chains that are matrizants and chains of associated pairs
The bitangential direct input scattering problems
Bitangential direct input impedance and spectral problems
Inverse monodromy problems
Bitangential Krein extension problems
Bitangential inverse input scattering problems
Bitangential inverse input impedance and spectral problems
Dirac-Krein systems