@article{JEDP_1977____164_0,
     author = {Pham The Lai and Robert, Didier},
     title = {Valeurs propres d'une classe d'\'equations diff\'erentielles singuli\`eres sur une demi-droite},
     journal = {Journ\'ees \'equations aux d\'eriv\'ees partielles},
     pages = {164--171},
     publisher = {Ecole polytechnique},
     year = {1977},
     mrnumber = {80j:34026},
     language = {fr},
     url = {http://www.numdam.org/item/JEDP_1977____164_0/}
}