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Overview of database and output of search.
| Database | Number of references | Number of references after duplication |
|---|---|---|
| Embase.com | 414 | 407 |
| Medline(Ovid) | 303 | 31 |
| Web-of-Science Core Collection | 381 | 131 |
| Cochrane Central | 9 | 6 |
| Google Scholar | 200 | 69 |
| Total 5th of December 2020 | 1,307 | 644 |
| Total updated search 14th of July 2020 | 65 | |
| Final total references screened | 709 |
