@article{MZ_1970__113_171282,
     author = {Hans-Berndt Brinkmann},
     title = {Addition von {Korrespondenzen} in abelschen {Kategorien.}},
     journal = {Mathematische Zeitschrift},
     pages = {344--352},
     year = {1970},
     volume = {113},
     zbl = {0194.01703},
     url = {http://geodesic.mathdoc.fr/item/MZ_1970__113_171282/}
}