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PRISMA flow diagram demonstrating the results of systematic literature search. Electronic search resulted in 243 entries. Twenty-four additional articles were identified through hand-searching. Of these 267 articles, 91 were excluded because they had been retrieved in more than one search. A total of 54 abstracts were reviewed and full-text analysis included 28 articles. Thirteen studies were finally included comprising one comparative study and 12 non-comparative studies.
