Owing to the fact that a Living Reviews in Relativity article may evolve over time, we recommend to cite the article as follows:
Duncan R. Lorimer,
"Binary and Millisecond Pulsars at the New Millennium",
Living Rev. Relativity 4, (2001), 5. URL (accessed <date>):
The date given as <date> then uniquely identifies the version of the article you are referring to.