Owing to the fact that a Living Reviews in Relativity article may evolve over time, we recommend to cite the article as follows:
Nils Andersson and Gregory L. Comer,
"Relativistic Fluid Dynamics: Physics for Many Different Scales",
Living Rev. Relativity 10, (2007), 1. URL (accessed <date>):
The date given as <date> then uniquely identifies the version of the article you are referring to.