Cita APA (7a ed.)

Christie, A. (1970). Towards zero (1st issued in Fontana Books, 4th impression.). Collins.

Cita Chicago Style (17a ed.)

Christie, Agatha. Towards Zero. 1st issued in Fontana Books, 4th impression. London [etc.]: Collins, 1970.

Cita MLA (9a ed.)

Christie, Agatha. Towards Zero. 1st issued in Fontana Books, 4th impression. Collins, 1970.