@article{MAN_1974__209_162586,
     author = {Claude Portenier},
     title = {Points extr\'emaux et densit\'e.},
     journal = {Mathematische Annalen},
     pages = {83--90},
     publisher = {mathdoc},
     volume = {209},
     year = {1974},
     zbl = {0267.46002},
     url = {http://geodesic.mathdoc.fr/item/MAN_1974__209_162586/}
}