@article{SM_1990_67_2_a5,
     author = {P. I. Naumkin and I. A. Shishmarev},
     title = {A periodic problem for {Whitham's} equation},
     journal = {Sbornik. Mathematics},
     pages = {403--426},
     publisher = {mathdoc},
     volume = {67},
     number = {2},
     year = {1990},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1990_67_2_a5/}
}