In addition to MEDLINE and EMBASE, which are generally considered to be the key international general healthcare databases, many countries and regions produce electronic bibliographic databases that concentrate on the literature produced in those regions, and which often include journals and other literature not indexed elsewhere. Access to many of these databases is available free of charge on the internet. Others are only available by subscription or on a ‘pay-as-you-go’ basis. Indexing complexity and consistency varies, as does the sophistication of the search interface, but they can be an important source of additional studies from journals not indexed in other international databases such as MEDLINE or EMBASE. Some examples are included in Box 6.2.a.