@article{1103859285,
author = {Sachs, R. K.},
title = {Spacetime $b$-boundaries},
journal = {Comm. Math. Phys.},
volume = {29},
number = {1},
year = {1973},
pages = { 215-220},
language = {en},
url = {http://dml.mathdoc.fr/item/1103859285}
}
Sachs, R. K. Spacetime $b$-boundaries. Comm. Math. Phys., Tome 29 (1973) no. 1, pp. 215-220. http://gdmltest.u-ga.fr/item/1103859285/