@article{RCM_1993__27_1-2_181864,
     author = {Graciela Silvia Birman},
     title = {Total absolute curvature of curves in {Lorentz} {Manifolds}},
     journal = {Revista colombiana de matematicas},
     pages = {9--14},
     year = {1993},
     volume = {27},
     number = {1-2},
     zbl = {0818.53002},
     url = {http://geodesic.mathdoc.fr/item/RCM_1993__27_1-2_181864/}
}