@article{SIGMA_2006_2_a12,
     author = {Siamak Khademi and Sadollah Nasiri},
     title = {Operator {Gauge} {Symmetry} in {QED}},
     journal = {Symmetry, integrability and geometry: methods and applications},
     year = {2006},
     volume = {2},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SIGMA_2006_2_a12/}
}