@article{DAN_1957_113_5_a5,
     author = {M. G. Krein},
     title = {On a continuous analogue of a {Christoffel} formula from the theory of orthogonal polynomials},
     journal = {Doklady Akademii Nauk},
     pages = {970--973},
     publisher = {mathdoc},
     volume = {113},
     number = {5},
     year = {1957},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1957_113_5_a5/}
}