@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},
     publisher = {mathdoc},
     volume = {2001},
     year = {2001},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/EJDE_2001__2001__a97/}
}