Karol Pak. Bertrand's Ballot Theorem. Formalized Mathematics, 22(2):119-123, 2014. [doi]
@article{Pak14b,
title = {Bertrand's Ballot Theorem},
author = {Karol Pak},
year = {2014},
url = {http://www.degruyter.com/view/j/forma.2014.22.issue-2/forma-2014-0014/forma-2014-0014.xml},
researchr = {https://researchr.org/publication/Pak14b},
cites = {0},
citedby = {0},
journal = {Formalized Mathematics},
volume = {22},
number = {2},
pages = {119-123},
}