@article{MZM_1980_28_4_a2,
     author = {V. S. Gerdjikov and E. Kh. Khristov},
     title = {Expansions in products of solutions of two {Dirac} systems},
     journal = {Matemati\v{c}eskie zametki},
     pages = {501--512},
     publisher = {mathdoc},
     volume = {28},
     number = {4},
     year = {1980},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1980_28_4_a2/}
}