@article{Shepperd01071957,
    Author = {Shepperd, J. A. H.},
    EPrint = {http://jlms.oxfordjournals.org/content/s1-32/3/277.full.pdf+html},
    File = {Betweenness Groups - Shepperd (0) (0) - a - a - f.pdf},
    Journal = {Journal of the London Mathematical Society},
    Keywords = {betweenness relation},
    Number = {3},
    Pages = {277-285},
    Title = {Betweenness Groups},
    URL = {http://jlms.oxfordjournals.org/content/s1-32/3/277.short},
    Volume = {s1-32},
    Year = {1957},
    bdsk-url-1 = {http://jlms.oxfordjournals.org/content/s1-32/3/277.short},
    bdsk-url-2 = {http://dx.doi.org/10.1112/jlms/s1-32.3.277},
    date-added = {2015-09-03 12:06:10 +0000},
    date-modified = {2015-09-03 12:06:27 +0000},
    doi = {10.1112/jlms/s1-32.3.277}
}

@article{Shepperd01071957, Author = {Shepperd, J. A. H.}, EPrint = {http://jlms.oxfordjournals.org/content/s1-32/3/277.full.pdf+html}, File = {Betweenness Groups - Shepperd (0) (0) - a - a - f.pdf}, Journal = {Journal of the London Mathematical Society}, Keywords = {betweenness relation}, Number = {3}, Pages = {277-285}, Title = {Betweenness Groups}, URL = {http://jlms.oxfordjournals.org/content/s1-32/3/277.short}, Volume = {s1-32}, Year = {1957}, bdsk-url-1 = {http://jlms.oxfordjournals.org/content/s1-32/3/277.short}, bdsk-url-2 = {http://dx.doi.org/10.1112/jlms/s1-32.3.277}, date-added = {2015-09-03 12:06:10 +0000}, date-modified = {2015-09-03 12:06:27 +0000}, doi = {10.1112/jlms/s1-32.3.277} }