Cochrane Reviews take the format of full-length methodological studies. Cochrane researchers will perform searches of medical databases including MEDLINE, PubMed and EMBASE; a continually updated database of trials called the Cochrane Central Register of Controlled Trials (CENTRAL); hand searching, where researchers look through entire libraries of scientific journals by hand and; reference checking of obtained articles in order to identify studies that are relevant to the question they are attempting to answer.