@article{10_4153_CJM_1980_010_0,
     author = {Avis, David},
     title = {On the {Extreme} {Rays} of the {Metric} {Cone}},
     journal = {Canadian journal of mathematics},
     pages = {126--144},
     year = {1980},
     volume = {32},
     number = {1},
     doi = {10.4153/CJM-1980-010-0},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CJM-1980-010-0/}
}