On the energy of Schwarzschild spacetime with the post-Newtonian approximation

With the post-Newtonian approximation, the energy of Schwarzschild spacetime in the Weinberg prescription is obtained. The energy for the first post-Newtonian approximation E-(1) = m gives the Newtonian treatment of Schwarzschild spacetime. However, for the second post-Newtonian approximation, the energy is shown that E-(1) adds extra terms E-(2) which consist of the energy stored in the configuration E-config, in the gravitational field E-field, and a term of surface integral. These extra terms give post-Newtonian corrections to the Newtonian treatment.