Cita APA (7a ed.)

Boer, M. d. (1991). Schengen: Intergovernmental scenario for European police co-operation. A system of European police co-operation in 1992.

Cita Chicago Style (17a ed.)

Boer, Monica den. "Schengen: Intergovernmental Scenario for European Police Co-operation." A System of European Police Co-operation in 1992 1991.

Cita MLA (8a ed.)

Boer, Monica den. "Schengen: Intergovernmental Scenario for European Police Co-operation." A System of European Police Co-operation in 1992, 1991.