http://europepmc.org/abstract/MED/23335386
http://europepmc.org/abstract/MED/22323480
http://europepmc.org/abstract/MED/27486981
http://europepmc.org/abstract/MED/23319568
http://europepmc.org/abstract/MED/24045501
http://europepmc.org/abstract/MED/21995386
http://europepmc.org/abstract/MED/24030381
http://europepmc.org/abstract/MED/21909114