@article{JCA_2013_20_3_JCA_2013_20_3_a3,
     author = {N. M. Nam and N. Hoang},
     title = {A {Generalized} {Sylvester} {Problem} and a {Generalized} {Fermat-Torricelli} {Problem}},
     journal = {Journal of convex analysis},
     pages = {669--687},
     publisher = {mathdoc},
     volume = {20},
     number = {3},
     year = {2013},
     url = {http://geodesic.mathdoc.fr/item/JCA_2013_20_3_JCA_2013_20_3_a3/}
}