@article{GDZPPN002104164, title = {Eisenstein cohomology of arithmetic groups. The case GL2.}, journal = {Inventiones mathematicae}, volume = {88}, year = {1987}, pages = {37-118}, zbl = {0629.10023}, url = {http://dml.mathdoc.fr/item/GDZPPN002104164} }
Harder, G. Eisenstein cohomology of arithmetic groups. The case GL2.. Inventiones mathematicae, Tome 88 (1987) pp. 37-118. http://gdmltest.u-ga.fr/item/GDZPPN002104164/