@article{10_37236_642,
     author = {William Y.C. Chen and Oliver X.Q. Gao and Peter L. Guo},
     title = {On {Han's} hook length formulas for trees},
     journal = {The electronic journal of combinatorics},
     year = {2011},
     volume = {18},
     number = {1},
     doi = {10.37236/642},
     zbl = {1250.05022},
     url = {http://geodesic.mathdoc.fr/articles/10.37236/642/}
}