@article{SMJ2_1997_23_2_a3,
     author = {Dragnev, Dragomir},
     title = {On the {Isoenergetical} {Non-Degeneracy} of the {Problem} of two {Centers} of {Gravitation}},
     journal = {Serdica Mathematical Journal},
     pages = {125--130},
     publisher = {mathdoc},
     volume = {23},
     number = {2},
     year = {1997},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SMJ2_1997_23_2_a3/}
}