@article{RM_1997_52_4_a0,
     author = {I. M. Gel'fand and M. I. Graev},
     title = {$GG$-functions and their relation to general hypergeometric functions},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     pages = {639--684},
     publisher = {mathdoc},
     volume = {52},
     number = {4},
     year = {1997},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/RM_1997_52_4_a0/}
}