@article{RM_2001_56_4_a0,
     author = {I. M. Gel'fand and M. I. Graev},
     title = {$\mathscr N$-functions and their relationship with solutions of general hypergeometric systems and $GG$-systems},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     pages = {615--647},
     publisher = {mathdoc},
     volume = {56},
     number = {4},
     year = {2001},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/RM_2001_56_4_a0/}
}