Conference papers can be some of the hardest forms of grey literature to locate.
They can be found in books (proceedings), journals (sometime as a special issue), databases, citation databases, websites, university repositories or not at all.
Conference proceedings may contribute valuable insights into a particular field of research and should be considered when undertaking a comprehensive literature review, particularly in science and health. The publication process for conference proceedings is normally shorter than for journals so they can provide insights into industry and discipline trends, as well as point to the most current research/studies/trials in a particular field. The information disseminated through conference proceedings is often not reported anywhere else, or at least not for some time.
The papers presented at a conference have often been accepted following a review process of either the full paper or just the abstract, however, not all published proceedings are peer reviewed so, as with any type of grey literature, it is important to assess the quality.