@article{IM_1988__91_3_143550,
     author = {Avner Ash},
     title = {Non-minimal modular symbols for {GL(n).}},
     journal = {Inventiones mathematicae},
     pages = {483--492},
     publisher = {mathdoc},
     volume = {91},
     number = {3},
     year = {1988},
     zbl = {0671.22005},
     url = {http://geodesic.mathdoc.fr/item/IM_1988__91_3_143550/}
}