1. Optimal database combinations for literature searches in systematic reviews: A prospective exploratory study;Bramer;Syst Rev,2017
2. Higgins JPT, Thomas J, Chandler J, et al. (2019). Cochrane Handbook for Systematic Reviews of Interventionsversion 6.1 (updated September 2020). Cochrane, 2020. Retrieved February 27, 2020, from https://training.cochrane.org/handbook
3. Identification of problems in search strategies in Cochrane reviews;Franco;Res Synth Methods,2018
4. A typology of reviews: An analysis of 14 review types and associated methodologies;Grant;Health Info Libr J,2009
5. Grey Literature Report. (n.d.). What is grey literature. Retrieved April 30, 2020, from https://www.greylit.org/about