http://europepmc.org/abstract/MED/22493355
http://europepmc.org/abstract/MED/15195137
http://europepmc.org/abstract/MED/20544847
http://europepmc.org/abstract/MED/20460471
http://europepmc.org/abstract/MED/19158841
http://europepmc.org/abstract/MED/25407517