APA (7th ed.) Citation

Leenders, T., Vlasman, T., & Marx, A. (1992). Policing after 1992: A challenge or a problem. Biermann.

Chicago Style (17th ed.) Citation

Leenders, Theo, Ton Vlasman, and Ad Marx. Policing After 1992: A Challenge or a Problem. Scherpenzeel: Biermann, 1992.

MLA (8th ed.) Citation

Leenders, Theo, et al. Policing After 1992: A Challenge or a Problem. Biermann, 1992.