@article{CMUC_2001_42_4_a0,
     author = {Bican, Ladislav and Torrecillas, Blas},
     title = {Relative exact covers},
     journal = {Commentationes Mathematicae Universitatis Carolinae},
     pages = {601--607},
     year = {2001},
     volume = {42},
     number = {4},
     mrnumber = {1883369},
     zbl = {1068.16039},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CMUC_2001_42_4_a0/}
}