@article{JOLT_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},
     year = {2008},
     volume = {18},
     number = {2},
     doi = {10.5802/jolt.505},
     zbl = {1148.53030},
     url = {https://jolt.centre-mersenne.org/articles/10.5802/jolt.505/}
}