@article{SMJ2_1999_25_1_a6,
     author = {Lucente, Sandra},
     title = {Nonlinear {Wave} {Equation} with {Vanishing} {Potential}},
     journal = {Serdica Mathematical Journal},
     pages = {71--82},
     publisher = {mathdoc},
     volume = {25},
     number = {1},
     year = {1999},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SMJ2_1999_25_1_a6/}
}