@article{DMTCS_2021_22_2_a7,
     author = {Albert, Michael and Jel{\'\i}nek, V{\'\i}t and Opler, Michal},
     title = {Two examples of {Wilf-collapse}},
     journal = {Discrete mathematics & theoretical computer science},
     publisher = {mathdoc},
     volume = {22},
     number = {2},
     year = {2020-2021},
     doi = {10.46298/dmtcs.5986},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.46298/dmtcs.5986/}
}