@article{1103840013, author = {Beiglb\"ock, W.}, title = {The center-of-mass in Einstein's theory of gravitation}, journal = {Comm. Math. Phys.}, volume = {4}, number = {1}, year = {1967}, pages = { 106-130}, language = {en}, url = {http://dml.mathdoc.fr/item/1103840013} }
Beiglböck, W. The center-of-mass in Einstein's theory of gravitation. Comm. Math. Phys., Tome 4 (1967) no. 1, pp. 106-130. http://gdmltest.u-ga.fr/item/1103840013/