@article{10_4153_CJM_1974_082_7,
     author = {Toubassi, E. H.},
     title = {The {Group} of {Extensions} and {Splitting} {Length}},
     journal = {Canadian journal of mathematics},
     pages = {879--883},
     year = {1974},
     volume = {26},
     number = {4},
     doi = {10.4153/CJM-1974-082-7},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CJM-1974-082-7/}
}