@article{ZNSL_2005_327_a7,
     author = {A. S. Kostenko},
     title = {The {Krein} string and characteristic functions of non-self-adjoint operators},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {115--134},
     year = {2005},
     volume = {327},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_2005_327_a7/}
}