There are several online materials on general relativity. Here I would like to get suggestions about concise review of general relativity at somewhat advanced level. The idea is that this should be enough for recapitulating the area at advanced level by somebody who had studied it thoroughly earlier but is out-of-touch with it for a long time. (Also one is not interested in learning all those stuff thoroughly again as that would be too time consuming.) I am not looking for just a list of important formula but compilation of all central concepts and the important results. Thanks.