Bulgarian Academy of Sciences. (1978). Abstracts of Bulgarian Scientific Literature. Scientific Information Centre.
Citação do estilo Chicago (17ª ed.)Bulgarian Academy of Sciences. Abstracts of Bulgarian Scientific Literature. Sofia: Scientific Information Centre, 1978.
Citação MLA (8ª ed.)Bulgarian Academy of Sciences. Abstracts of Bulgarian Scientific Literature. Scientific Information Centre, 1978.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.