http://europepmc.org/abstract/MED/27288520
http://europepmc.org/abstract/MED/27276561
http://europepmc.org/abstract/MED/27997762
http://europepmc.org/abstract/MED/21030981
http://europepmc.org/abstract/MED/22237025
http://europepmc.org/abstract/MED/27881874