http://europepmc.org/abstract/MED/27149842
http://europepmc.org/abstract/MED/24755471
http://europepmc.org/abstract/MED/22327622
http://europepmc.org/abstract/MED/28548125
http://europepmc.org/abstract/MED/23700467
http://europepmc.org/abstract/MED/24951259