@article{10_4064_sm_131_1_89_94,
     author = {Ryszard Szwarc},
     title = {The ratio and generating function of cogrowth coefficients of finitely generated groups},
     journal = {Studia Mathematica},
     pages = {89--94},
     publisher = {mathdoc},
     volume = {131},
     number = {1},
     year = {1998},
     doi = {10.4064/sm-131-1-89-94},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/sm-131-1-89-94/}
}