APA

Nat. centre for inform. and documentation, . (2005). ADVANCES IN BULGARIAN SCIENCE. : Nat. centre for inform. and documentation.

Chicago

Nat. centre for inform. and documentation, . 2005. ADVANCES IN BULGARIAN SCIENCE. : Nat. centre for inform. and documentation.

Harvard

Nat. centre for inform. and documentation, . (2005). ADVANCES IN BULGARIAN SCIENCE. : Nat. centre for inform. and documentation.

MLA

Nat. centre for inform. and documentation, . ADVANCES IN BULGARIAN SCIENCE. : Nat. centre for inform. and documentation. 2005.