@article{MZ_1968__107_171056,
     author = {Ulrich Oberst},
     title = {Homology of {Categories} and {Exactness} of {Direct} {Limits.}},
     journal = {Mathematische Zeitschrift},
     pages = {87--115},
     publisher = {mathdoc},
     volume = {107},
     year = {1968},
     zbl = {0176.28902},
     url = {http://geodesic.mathdoc.fr/item/MZ_1968__107_171056/}
}