TABLE 1—
Systematic Review Article Type by Frequency: January 2009–May 2012
| Study Type | Articles (n = 98), No. (%) |
| Empirical study | |
| Experimental design | 0 |
| Observational design | 11 (11) |
| Modeling | 6 (6) |
| Review article | 28 (29) |
| Commentary | 53 (54) |
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