@article{MAN_1991__290_4_164820,
     author = {Norbert Schappacher and Anthony J. Scholl},
     title = {The boundary of the {Eisenstein} symbol.},
     journal = {Mathematische Annalen},
     pages = {303--322},
     publisher = {mathdoc},
     volume = {290},
     number = {4},
     year = {1991},
     zbl = {0729.11027},
     url = {http://geodesic.mathdoc.fr/item/MAN_1991__290_4_164820/}
}