@article{MZ_1976__148_172368,
     author = {Volker Z\"oberlein},
     title = {Doctrines on {2-Categories.}},
     journal = {Mathematische Zeitschrift},
     pages = {267--280},
     publisher = {mathdoc},
     volume = {148},
     year = {1976},
     zbl = {0311.18005},
     url = {http://geodesic.mathdoc.fr/item/MZ_1976__148_172368/}
}