Cita APA (7a ed.)

Billingsley, R. (2001). Informers: Policing, policy, practice (1. publ.). Willan.

Cita Chicago Style (17a ed.)

Billingsley, Roger. Informers: Policing, Policy, Practice. 1. publ. Cullompton: Willan, 2001.

Cita MLA (8a ed.)

Billingsley, Roger. Informers: Policing, Policy, Practice. 1. publ. Willan, 2001.