Nursing - Doctoral Students

Gray literature is literature that has been published, but the publishing process did not go through traditional commercial publishing pathway. 

Professional organizations, government departments & agencies, and others such as the Pew Research Center and AARP publish their own resources. These works are considered "gray."

       Gray Literature

Hopewell S, Loudon K, Clarke Mike J, Oxman Andrew D, Dickersin K. Publication bias in clinical trials due to statistical significance or direction of trial results. 
Cochrane Database of Systematic Reviews [serial on the  Internet]. 2009; (1): MR000006. http://www.ncbi.nlm.nih.gov/pubmed/19160345