Tom Fowler, Ira M. Gessel, Gilbert Labelle, Pierre Leroux. The Specification of 2-trees. Adv. Appl. Math., 28(2):145-168, 2002. [doi]
@article{FowlerGLL02,
title = {The Specification of 2-trees},
author = {Tom Fowler and Ira M. Gessel and Gilbert Labelle and Pierre Leroux},
year = {2002},
doi = {10.1006/aama.2001.0771},
url = {https://doi.org/10.1006/aama.2001.0771},
researchr = {https://researchr.org/publication/FowlerGLL02},
cites = {0},
citedby = {0},
journal = {Adv. Appl. Math.},
volume = {28},
number = {2},
pages = {145-168},
}