APA

Hristova V., Popov J. & Stefanova V. (1989). La perestrojka. : Sofia Press.

Chicago

Hristova Veliana, Popov Jurij and Stefanova Vesela. 1989. La perestrojka. : Sofia Press.

Harvard

Hristova V., Popov J. and Stefanova V. (1989). La perestrojka. : Sofia Press.

MLA

Hristova Veliana, Popov Jurij and Stefanova Vesela. La perestrojka. : Sofia Press. 1989.