@article{GDZPPN00254203X,
title = {Total absolute curvature of curves in Lorentz Manifolds},
journal = {Revista colombiana de matematicas},
volume = {27},
year = {1993},
pages = {9-14},
zbl = {0818.53002},
url = {http://dml.mathdoc.fr/item/GDZPPN00254203X}
}
Birman, Graciela Silvia. Total absolute curvature of curves in Lorentz Manifolds. Revista colombiana de matematicas, Tome 27 (1993) pp. 9-14. http://gdmltest.u-ga.fr/item/GDZPPN00254203X/