A number of Belarusian online electronic libraries exist where you can find texts that are unavailable on the shelves of the library. Here is one:
Belarusian electronic library covering all subjects including language and literature.
Here are some examples of websites which are relevant to Belarusian literature:
This is the website of the Belarus free theatre, a Belarusian underground theatre group.
Poems of Belarusian poets: Belarusian national poetry portal.
Fundamentals of Modern Belarusian
Pedagogical grammar in PDF format.