Demographic aspects of educational planning. 2026-02-16T06:13:51+03:00 DEBUG: VuFind\ILS\Driver\Folio: Token taken from global cache: eyJhbGciOiJIUzI1NiJ9.eyJzdWIiO... - Ta, Ngoc Chau ([United Nations Educational, Scientific and Cultural Organization. Document] IIEP.66/II.9/A, 1969)