@article{10_4064_cm114_1_6,
     author = {Wolfgang Rump and Yi Chuan Yang},
     title = {The essential cover and the absolute cover
 of a schematic space},
     journal = {Colloquium Mathematicum},
     pages = {53--75},
     publisher = {mathdoc},
     volume = {114},
     number = {1},
     year = {2009},
     doi = {10.4064/cm114-1-6},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/cm114-1-6/}
}