http://europepmc.org/abstract/MED/25078331
http://europepmc.org/abstract/MED/22526905
http://europepmc.org/abstract/MED/24747642
http://europepmc.org/abstract/MED/22539591
http://europepmc.org/abstract/MED/17289876
http://europepmc.org/abstract/MED/23585556
http://europepmc.org/abstract/MED/27589897