@article{Moher2009,
author = {Moher, D. and Liberati, A. and Tetzlaff, J. and Altman, D.G.},
title= {Preferred reporting items for systematic reviews and meta-analyses: The PRISMA Statement},
year = {2009},
doi = {10.1136/bmj.b2535},
volume = {339},
number = {7716},
pages = {332--336},
}