@article{10_1090_S0894_0347_1990_1007910_7,
     author = {Wilf, Herbert S. and Zeilberger, Doron},
     title = {Rational functions certify combinatorial identities},
     journal = {Journal of the American Mathematical Society},
     pages = {147--158},
     publisher = {mathdoc},
     volume = {03},
     number = {1},
     year = {1990},
     doi = {10.1090/S0894-0347-1990-1007910-7},
     url = {http://geodesic.mathdoc.fr/articles/10.1090/S0894-0347-1990-1007910-7/}
}