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Search methodology of the included studies
| First author (year) | Restriction of publication language | Restriction of publication status | Search database | |||||
|---|---|---|---|---|---|---|---|---|
| PubMed | MEDLINE | Embase | Cochrane Library | CINAHL | Others | |||
| Khan RJ (2005) | No | No | + | + | + | + | + | |
| Khan RJ (2010) | No | No | + | + | + | + | + | |
| McMahon SE (2011) | No | No | + | + | + | + | + | |
| Jones MP (2012) | No | No | + | + | + | + | + | |
