APA

christie، agatha, . (2015). The secret adversary. [un known]: el horya،.

Chicago

christie، agatha, . 2015. The secret adversary. [un known]: el horya،.

Harvard

christie، agatha, . (2015). The secret adversary. [un known]: el horya،.

MLA

christie، agatha, . The secret adversary. [un known]: el horya،. 2015.