Não informado. (1957). Abstracts of Bulgarian Scientific Literature. Centre of Scientific Information and Documentation.
Čikaški stil citiranja (17. izdanje)Não informado. Abstracts of Bulgarian Scientific Literature. Sofia: Centre of Scientific Information and Documentation, 1957.
MLA način citiranja (8. izdanje)Não informado. Abstracts of Bulgarian Scientific Literature. Centre of Scientific Information and Documentation, 1957.
Upozorenje: Ovi citati možda nisu uvijek 100% točni.