http://europepmc.org/abstract/MED/15825690
http://europepmc.org/abstract/MED/24625776
http://europepmc.org/abstract/MED/28481359
http://europepmc.org/abstract/MED/17620607
http://europepmc.org/abstract/MED/28945843
http://europepmc.org/abstract/MED/15135005
http://europepmc.org/abstract/MED/10675480
http://europepmc.org/abstract/MED/22493262