@article{JLT_2008_18_2_JLT_2008_18_2_a12,
     author = {P. Birtea and J.-P. Ortega and T. S. Ratiu },
     title = {A {Local-to-Global} {Principle} for {Convexity} in {Metric} {Spaces}},
     journal = {Journal of Lie theory},
     pages = {445--469},
     publisher = {mathdoc},
     volume = {18},
     number = {2},
     year = {2008},
     url = {http://geodesic.mathdoc.fr/item/JLT_2008_18_2_JLT_2008_18_2_a12/}
}