@article{SIGMA_2007_3_a114,
     author = {Ibrar Hussain and Fazal M. Mahomed and Asghar Qadir},
     title = {Second-Order {Approximate} {Symmetries} of the {Geodesic} {Equations} for the {Reissner{\textendash}Nordstr\"om} {Metric} and},
     journal = {Symmetry, integrability and geometry: methods and applications},
     year = {2007},
     volume = {3},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SIGMA_2007_3_a114/}
}