@article{MOMA_1989__107_3_178409,
     author = {Jean-Philippe Anker},
     title = {A {Short} {Proof} of a {Classical} {Covering} {Lemma.}},
     journal = {Monatshefte f\"ur Mathematik},
     pages = {5--8},
     publisher = {mathdoc},
     volume = {107},
     number = {3},
     year = {1989},
     zbl = {0671.22001},
     url = {http://geodesic.mathdoc.fr/item/MOMA_1989__107_3_178409/}
}