@article{GDZPPN00248448X,
title = {Covering Sets by Subsets.},
journal = {Monatshefte f\"ur Mathematik},
volume = {98},
year = {1984},
pages = {323-330},
zbl = {0545.05006},
url = {http://dml.mathdoc.fr/item/GDZPPN00248448X}
}
Warlimont, Richard. Covering Sets by Subsets.. Monatshefte für Mathematik, Tome 98 (1984) pp. 323-330. http://gdmltest.u-ga.fr/item/GDZPPN00248448X/