@article{RM_1978_33_1_a21,
     author = {B. V. Yusin},
     title = {Proof of a variational relation between the coefficients of the
},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     pages = {223--224},
     publisher = {mathdoc},
     volume = {33},
     number = {1},
     year = {1978},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/RM_1978_33_1_a21/}
}