@article{10_37236_88,
     author = {Sergey Kitaev and Jeffrey Liese and Jeffrey Remmel and Bruce E. Sagan},
     title = {Rationality, irrationality, and {Wilf} equivalence in generalized factor order},
     journal = {The electronic journal of combinatorics},
     year = {2009},
     volume = {16},
     number = {2},
     doi = {10.37236/88},
     zbl = {1187.05010},
     url = {http://geodesic.mathdoc.fr/articles/10.37236/88/}
}