@article{TAC_2007_18_a3,
     author = {Joao Faria Martins and Timothy Porter},
     title = {On {Yetter's} {Invariant} and an {Extension} of the {Dijkgraaf-Witten} {Invariant} to {Categorical} {Groups}},
     journal = {Theory and applications of categories},
     pages = {118--150},
     publisher = {mathdoc},
     volume = {18},
     year = {2007},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/TAC_2007_18_a3/}
}