Não informado. (1978). Abstracts of bulgarian scientific literature. Central Institute for Scientific, Technical and Economic Information.
Chicago-Zitierstil (17. Ausg.)Não informado. Abstracts of Bulgarian Scientific Literature. Sofia: Central Institute for Scientific, Technical and Economic Information, 1978.
MLA-Zitierstil (8. Ausg.)Não informado. Abstracts of Bulgarian Scientific Literature. Central Institute for Scientific, Technical and Economic Information, 1978.
Achtung: Diese Zitate sind unter Umständen nicht zu 100% korrekt.