Mark E. Kidwell, Donald E. Knuth, O. P. Lossers. Leaves of Ordered Trees: 10757. The American Mathematical Monthly, 108(9):874-875, 2001. [doi]
@article{KidwellKL01, title = {Leaves of Ordered Trees: 10757}, author = {Mark E. Kidwell and Donald E. Knuth and O. P. Lossers}, year = {2001}, url = {http://www.jstor.org/stable/2695570}, researchr = {https://researchr.org/publication/KidwellKL01}, cites = {0}, citedby = {0}, journal = {The American Mathematical Monthly}, volume = {108}, number = {9}, pages = {874-875}, }