Top Databases and some advice
Are you looking for a topic, but not necessarily a particular country outside of the United States? ERIC usually tags those articles with foreign countries or cross cultural studies. Education Source usually tags with the name of the particular country. If more than one country it uses cross cultural studies.
Try adding more terms: international, terms for different regions or types of countries (Africa*, Europe*, Latin America*, South America* developing countries)
If you can narrow your results without adding the geographic component, it may be more efficient to browse the results.
Annual Bibliographies, Comparative Education
Need to get some ideas? The journal Comparative Education Review publishes a bibliography on comparative and international education every year covering research in the field (and not just within that one journal).
Background Sources, Reference Books
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