@article{AIHPA_1975__22_2_159_0, author = {Esposito, R. and Gallavotti, G.}, title = {Approximate symmetries and their spontaneous breakdown}, journal = {Annales de l'institut Henri Poincar\'e. Section A, Physique Th\'eorique}, pages = {159--172}, year = {1975}, publisher = {Gauthier-Villars}, volume = {22}, number = {2}, mrnumber = {389108}, language = {en}, url = {https://www.numdam.org/item/AIHPA_1975__22_2_159_0/} }