http://europepmc.org/abstract/MED/23204322
http://europepmc.org/abstract/MED/2841597
http://europepmc.org/abstract/MED/22609129
http://europepmc.org/abstract/MED/10612810
http://europepmc.org/abstract/MED/12438234
http://europepmc.org/abstract/MED/20233436
http://europepmc.org/abstract/MED/27656095