@article{CMUC_1974_15_1_a14,
     author = {Tiller, John},
     title = {Unions in $E-M$ categories and coreflective subcategories},
     journal = {Commentationes Mathematicae Universitatis Carolinae},
     pages = {173--187},
     year = {1974},
     volume = {15},
     number = {1},
     mrnumber = {0338114},
     zbl = {0281.18001},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CMUC_1974_15_1_a14/}
}