http://europepmc.org/abstract/MED/18772396
http://europepmc.org/abstract/MED/28481359
http://europepmc.org/abstract/MED/26496030
http://europepmc.org/abstract/MED/24705251
http://europepmc.org/abstract/MED/25740784
http://europepmc.org/abstract/MED/25471132
http://europepmc.org/abstract/MED/23917401
http://europepmc.org/abstract/MED/22286061