@article{CMUC_1965__6_4_a7,
     author = {Trnkov\'a, V\v{e}ra},
     title = {Sum of categories with amalgamated subcategory},
     journal = {Commentationes Mathematicae Universitatis Carolinae},
     pages = {449--474},
     publisher = {mathdoc},
     volume = {06},
     number = {4},
     year = {1965},
     mrnumber = {0190208},
     zbl = {0138.01701},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CMUC_1965__6_4_a7/}
}