Não informado. (1971). Educational broadcasting international. Centre for Educational Television Overseas.
শিকাগো স্টাইল (17 তম সংস্করণ) উদ্ধৃতিNão informado. Educational Broadcasting International. London: Centre for Educational Television Overseas, 1971.
M.L.A (8 ম সংস্করণ) উদ্ধৃতিNão informado. Educational Broadcasting International. Centre for Educational Television Overseas, 1971.
সতর্কবাণী: সাইটেশন সবসময় 100% নির্ভুল হতে পারে না.