@article{CM_1987__63_3_409_0,
     author = {Ulbrich, K.-H.},
     title = {On cohomology of graded group categories},
     journal = {Compositio Mathematica},
     pages = {409--417},
     publisher = {Martinus Nijhoff Publishers},
     volume = {63},
     number = {3},
     year = {1987},
     mrnumber = {909387},
     zbl = {0628.18006},
     language = {en},
     url = {http://archive.numdam.org/item/CM_1987__63_3_409_0/}
}