If you have access via a university library (international students, take note), HathiTrust has scanned physical copies of Avramov’s works. You can search for "Smilja Avramov" and download full PDFs of books published before 1998 in the US.

If you are looking for physical editions for a paper or library, they are often available through specialized retailers: : Lists several titles including Genocide in Yugoslavia and Trilaterale Kommission Amazon Author Page Everand : Offers e-book versions of some titles, such as Trilaterale Kommission SMILJA AVRAMOV: Books - Amazon.com