@article{CM_1987__64_3_329_0,
     author = {Heckman, G. J. and Opdam, E. M.},
     title = {Root systems and hypergeometric functions. {I}},
     journal = {Compositio Mathematica},
     pages = {329--352},
     publisher = {Martinus Nijhoff Publishers},
     volume = {64},
     number = {3},
     year = {1987},
     mrnumber = {918416},
     zbl = {0656.17006},
     language = {en},
     url = {http://www.numdam.org/item/CM_1987__64_3_329_0/}
}