The National Library of Belarus

The National Library of Belarus (Belarusian: Нацыянальная бібліятэка Беларусі, Russian: Национальная библиотека Беларуси), founded on 15 September 1922, is a copyright library of the Republic of Belarus. It houses the largest collection of Belarusian printed materials and the third largest collection of books in Russian behind the Russian State Library (Moscow) and the Russian National Library (St Petersburg).

More information on the Wikpedia page

The website, in Belarus, English and Russian is.