@article{EJDE_2001__2001__a97,
     author = {Ibragimov,  R.N.},
     title = {Approximate equivalence transformations and invariant solutions of a perturbed nonlinear wave equation},
     journal = {Electronic journal of differential equations},
     year = {2001},
     volume = {2001},
     zbl = {0986.58021},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/EJDE_2001__2001__a97/}
}