This very comprehensive wiki provides information about systematic reviews and other knowledge syntheses, including guides, manuals and advice.
I wrote an article with two of my colleagues about scoping reviews. It not only discusses the role of the librarian but also provides an overview of what a scoping review is and of methodological best practices.
Morris, M., Boruff, J. T., & Gore, G. (2016). Scoping reviews: establishing the role of the librarian. Journal of the Medical Library Association. 104, 346-353. doi:10.3163/1536-5050.104.4.020