APA (7th ed.) Citation

Hopewell, S., & Clarke, M. (2004). Impact of grey literature on systematic reviews of randomized trials.

Chicago Style (17th ed.) Citation

Hopewell, S., and M. Clarke. Impact of Grey Literature on Systematic Reviews of Randomized Trials. 2004.

MLA (9th ed.) Citation

Hopewell, S., and M. Clarke. Impact of Grey Literature on Systematic Reviews of Randomized Trials. 2004.

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