@article{10_4153_CMB_1975_001_5,
     author = {Barr, Michael},
     title = {The {Existence} of {Injective} {Effacements}},
     journal = {Canadian mathematical bulletin},
     pages = {1--6},
     year = {1975},
     volume = {18},
     number = {1},
     doi = {10.4153/CMB-1975-001-5},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CMB-1975-001-5/}
}