@article{10_4153_CJM_1974_072_0,
     author = {Dietze, Anke and Schaps, Mary},
     title = {Determining {Subgroups} of a {Given} {Finite} {Index} in a {Finitely} {Presented} {Group}},
     journal = {Canadian journal of mathematics},
     pages = {769--782},
     year = {1974},
     volume = {26},
     number = {4},
     doi = {10.4153/CJM-1974-072-0},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CJM-1974-072-0/}
}