Key points are not available for this paper at this time.
It is shown that, in space-times which are asymptotically flat, there are reasonable physical restrictions that allow one to impose coordinate conditions (in addition to the usual Bondi-type conditions)which restrict the allowed coordinate group to a subgroup of the Bondi-Metzner-Sachs group. This subgroup is isomorphic to the improper orthochronous inhomogeneous Lorentz group.
Newman et al. (Sun,) studied this question.