http://europepmc.org/abstract/MED/25750087
http://europepmc.org/abstract/MED/19498322
http://europepmc.org/abstract/MED/24747643
http://europepmc.org/abstract/MED/28973495
http://europepmc.org/abstract/MED/17854394
http://europepmc.org/abstract/MED/24700472
http://europepmc.org/abstract/MED/27468715
http://europepmc.org/abstract/MED/25743702
http://europepmc.org/abstract/MED/27389594