http://europepmc.org/abstract/MED/2064725
http://europepmc.org/abstract/MED/8453633
http://europepmc.org/abstract/MED/1913619
http://europepmc.org/abstract/MED/25759019
http://europepmc.org/abstract/MED/2179417
http://europepmc.org/abstract/MED/19849697
http://europepmc.org/abstract/MED/8426854
http://europepmc.org/abstract/MED/23337891