C. J. Everett, P. R. Stein. The combinatorics of random walk with absorbing barriers. Discrete Mathematics, 17(1):27-45, 1977. [doi]
@article{EverettS77,
title = {The combinatorics of random walk with absorbing barriers},
author = {C. J. Everett and P. R. Stein},
year = {1977},
doi = {10.1016/0012-365X(77)90019-X},
url = {http://dx.doi.org/10.1016/0012-365X(77)90019-X},
researchr = {https://researchr.org/publication/EverettS77},
cites = {0},
citedby = {0},
journal = {Discrete Mathematics},
volume = {17},
number = {1},
pages = {27-45},
}