@article{SM_1989_63_2_a3,
     author = {S. V. Matveev and A. T. Fomenko and V. V. Sharko},
     title = {Round {Morse} functions and isoenergy surfaces of integrable {Hamiltonian} systems},
     journal = {Sbornik. Mathematics},
     pages = {319--336},
     publisher = {mathdoc},
     volume = {63},
     number = {2},
     year = {1989},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1989_63_2_a3/}
}