Owing to the fact that a Living Reviews in Relativity article may evolve over time, we recommend to cite the article as follows:
Toshifumi Futamase and Yousuke Itoh,
"The Post-Newtonian Approximation for Relativistic Compact Binaries",
Living Rev. Relativity 10, (2007), 2. URL (accessed <date>):
The date given as <date> then uniquely identifies the version of the article you are referring to.