http://europepmc.org/abstract/MED/25957691
http://europepmc.org/abstract/MED/24755471
http://europepmc.org/abstract/MED/26071483
http://europepmc.org/abstract/MED/22895193
http://europepmc.org/abstract/MED/25344691
http://europepmc.org/abstract/MED/22810696