1. Christián, L. (2022). Komplementer Rendészet (Complementary law enforcement). Dialog Campus.
2. Christián, L., & Bartóki-Gönczy, B. (2018). Actual questions of the Hungarian private security market. Internal Security, 10(2), 177–186.
3. Christián, L., & Rottler, V. (2021). Magánbiztonsági helyzetértékelés 2019–2020 (Evaluation of private security sector). Glossa Iuridica, 8(1–2), 159–182.
4. Christián, L., & Sotlar, A. (2018). Private security regulation in Hungary and Slovenia – A comparative study based on legislation and societal foundations. Varstvoslovje, 20(2), 143–162.
5. Crawford, A. (2014). Police, policing and future of the policing family. In J. M. Brown (Ed.), The future of policing. Routledge.