Owing to the fact that a Living Reviews in Relativity article may evolve over time, we recommend to cite the article as follows:
David Merritt and Miloš Milosavljević,
"Massive Black Hole Binary Evolution",
Living Rev. Relativity 8, (2005), 8. URL (accessed <date>):
The date given as <date> then uniquely identifies the version of the article you are referring to.