@article{JEDP_1974____A2_0,
     author = {Pr\'evosto, Dominique and Rolland, Jacques},
     title = {Th\'eor\`eme d'indice et r\'egularit\'e pour une classe d'op\'erateurs elliptiques et d\'eg\'en\'er\'es},
     journal = {Journ\'ees \'equations aux d\'eriv\'ees partielles},
     eid = {2},
     pages = {1--36},
     publisher = {Ecole polytechnique},
     year = {1974},
     mrnumber = {51 #8631},
     language = {fr},
     url = {http://www.numdam.org/item/JEDP_1974____A2_0/}
}