@article{PS_2013__17__635_0,
     author = {Charlier, Benjamin},
     title = {Necessary and sufficient condition for the existence of a {Fr\'echet} mean on the circle},
     journal = {ESAIM: Probability and Statistics},
     pages = {635--649},
     publisher = {EDP-Sciences},
     volume = {17},
     year = {2013},
     doi = {10.1051/ps/2012015},
     mrnumber = {3126155},
     language = {en},
     url = {http://www.numdam.org/articles/10.1051/ps/2012015/}
}