@article{RCM_1998_32_1_a4,
     author = {LUIS A. ANCHORDOQUI and GRACIELA S. BIRMAN (Un and Metric tensor for homogeneous and isotropic},
     title = { 5-dimensional pseudo {Riemannian} {Models}},
     journal = {Revista colombiana de matematicas},
     pages = {73--79},
     publisher = {mathdoc},
     volume = {32},
     number = {1},
     year = {1998},
     url = {http://geodesic.mathdoc.fr/item/RCM_1998_32_1_a4/}
}