Owing to the fact that a Living Reviews in Relativity article may evolve over time, we recommend to cite the article as follows:
Olivier Sarbach and Manuel Tiglio,
"Continuum and Discrete Initial-Boundary Value Problems and Einstein's Field Equations",
Living Rev. Relativity 15, (2012), 9. URL (accessed <date>):
The date given as <date> then uniquely identifies the version of the article you are referring to.