@article{ASENS_1965_3_82_2_297_0,
     author = {Akutowicz, Edwin J.},
     title = {Sur l'approximation spectrale},
     journal = {Annales scientifiques de l'\'Ecole Normale Sup\'erieure},
     pages = {297--325},
     publisher = {Elsevier},
     volume = {3e s{\'e}rie, 82},
     number = {2},
     year = {1965},
     doi = {10.24033/asens.1142},
     mrnumber = {35 #5863},
     zbl = {0166.39902},
     language = {fr},
     url = {http://archive.numdam.org/articles/10.24033/asens.1142/}
}