http://europepmc.org/abstract/MED/8110876
http://europepmc.org/abstract/MED/25343957
http://europepmc.org/abstract/MED/23856246
http://europepmc.org/abstract/MED/11681414
http://europepmc.org/abstract/MED/2040694
http://europepmc.org/abstract/MED/7658697