@article{10_37236_9051,
     author = {Westin King and Catherine H. Yan},
     title = {Parking functions on directed graphs and some directed trees},
     journal = {The electronic journal of combinatorics},
     year = {2020},
     volume = {27},
     number = {2},
     doi = {10.37236/9051},
     zbl = {1441.05024},
     url = {http://geodesic.mathdoc.fr/articles/10.37236/9051/}
}