@article{10_4153_CMB_1970_088_0,
     author = {Luedeman, John K.},
     title = {A {Note} on the {\ensuremath{\Sigma}(S)-Injectivity} of {R(S)}},
     journal = {Canadian mathematical bulletin},
     pages = {481--489},
     year = {1970},
     volume = {13},
     number = {4},
     doi = {10.4153/CMB-1970-088-0},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CMB-1970-088-0/}
}