http://europepmc.org/abstract/MED/26608593
http://europepmc.org/abstract/MED/24837465
http://europepmc.org/abstract/MED/28481359
http://europepmc.org/abstract/MED/29386642
http://europepmc.org/abstract/MED/24531327
http://europepmc.org/abstract/MED/21796119
http://europepmc.org/abstract/MED/23861822
http://europepmc.org/abstract/MED/26647218