@article{10_4153_CJM_1966_096_9,
     author = {Freese, Raymond W. and Andalafte, Edward Z.},
     title = {A {Characterization} of {2-Betweenness} in {2-Metric} {Spaces}},
     journal = {Canadian journal of mathematics},
     pages = {963--968},
     year = {1966},
     volume = {18},
     number = {1},
     doi = {10.4153/CJM-1966-096-9},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CJM-1966-096-9/}
}