APA

Viola L., . (2007). The unknown gulag. New York: Oxford University Press.

Chicago

Viola Lynne, . 2007. The unknown gulag. New York: Oxford University Press.

Harvard

Viola L., . (2007). The unknown gulag. New York: Oxford University Press.

MLA

Viola Lynne, . The unknown gulag. New York: Oxford University Press. 2007.