@article{PIM_1971_N_S_12_26_a0,
     author = {Milorad Bertolino},
     title = {Tuyaux {\'Etag\'es} {De} {L'Approximation} {Des} {\'Equations} {Diff\'erentielles}},
     journal = {Publications de l'Institut Math\'ematique},
     pages = {5 },
     publisher = {mathdoc},
     volume = {_N_S_12},
     number = {26},
     year = {1971},
     url = {http://geodesic.mathdoc.fr/item/PIM_1971_N_S_12_26_a0/}
}