@article{MZM_1992_51_6_a16,
     author = {A. M. Akhtyamov},
     title = {Calculation of the coefficients of expansions in derivative chains of a spectral problem},
     journal = {Matemati\v{c}eskie zametki},
     pages = {137--139},
     publisher = {mathdoc},
     volume = {51},
     number = {6},
     year = {1992},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1992_51_6_a16/}
}