@article{10_4171_dm_847,
     author = {Wolfgang Woess},
     title = {Ratio limits and {Martin} boundary},
     journal = {Documenta mathematica},
     pages = {1501--1528},
     year = {2021},
     volume = {26},
     doi = {10.4171/dm/847},
     url = {http://geodesic.mathdoc.fr/articles/10.4171/dm/847/}
}