http://europepmc.org/abstract/MED/27288520
http://europepmc.org/abstract/MED/27276561
http://europepmc.org/abstract/MED/21030981
http://europepmc.org/abstract/MED/27881874
http://europepmc.org/abstract/MED/26980726
http://europepmc.org/abstract/MED/27885656
http://europepmc.org/abstract/MED/21736506