APA (7th ed.) Citation

Hackmann, A., Ehlers, A., Speckens, A., & Clark, D. (2004). Characteristics and content of intrusive memories in PTSD and their changes with treatment.

Chicago Style (17th ed.) Citation

Hackmann, A., A. Ehlers, A. Speckens, and D. Clark. Characteristics and Content of Intrusive Memories in PTSD and Their Changes with Treatment. 2004.

MLA (9th ed.) Citation

Hackmann, A., et al. Characteristics and Content of Intrusive Memories in PTSD and Their Changes with Treatment. 2004.

Warning: These citations may not always be 100% accurate.