@article{ETNA_2007__27__a4,
     author = {Koepf,  Wolfram},
     title = {Orthogonal polynomials and recurrence equations, operator equations and factorization},
     journal = {Electronic transactions on numerical analysis},
     pages = {113--123},
     year = {2007},
     volume = {27},
     zbl = {1176.33012},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/ETNA_2007__27__a4/}
}