http://europepmc.org/abstract/MED/22323480
http://europepmc.org/abstract/MED/27029036
http://europepmc.org/abstract/MED/22932795
http://europepmc.org/abstract/MED/27127180
http://europepmc.org/abstract/MED/24030381
http://europepmc.org/abstract/MED/22238327