@article{AIHPA_1974__21_4_341_0,
     author = {Rafique, M. and Tahir Shah, K.},
     title = {Invariant operators of inhomogeneous unitary group},
     journal = {Annales de l'I.H.P. Physique th\'eorique},
     pages = {341--345},
     publisher = {Gauthier-Villars},
     volume = {21},
     number = {4},
     year = {1974},
     mrnumber = {372126},
     zbl = {0303.17004},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/AIHPA_1974__21_4_341_0/}
}