APA সাইটেশন

UNESCO. (1999). Adult learning and the challenges of the 21st century. UNESCO.

শিকাগো স্টাইলে সাইটেশন

UNESCO. Adult Learning and the Challenges of the 21st Century. Germany: UNESCO, 1999.

এমএলএ সাইটেশন

UNESCO. Adult Learning and the Challenges of the 21st Century. UNESCO, 1999.