http://europepmc.org/abstract/MED/19923868
http://europepmc.org/abstract/MED/28481359
http://europepmc.org/abstract/MED/24122611
http://europepmc.org/abstract/MED/25244542
http://europepmc.org/abstract/MED/2199641
http://europepmc.org/abstract/MED/27852700