@article{AIHPA_1975__22_2_159_0,
     author = {Esposito, R. and Gallavotti, G.},
     title = {Approximate symmetries and their spontaneous breakdown},
     journal = {Annales de l'I.H.P. Physique th\'eorique},
     pages = {159--172},
     publisher = {Gauthier-Villars},
     volume = {22},
     number = {2},
     year = {1975},
     mrnumber = {389108},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/AIHPA_1975__22_2_159_0/}
}