http://europepmc.org/abstract/MED/18186519
http://europepmc.org/abstract/MED/27149842
http://europepmc.org/abstract/MED/24755471
http://europepmc.org/abstract/MED/28481359
http://europepmc.org/abstract/MED/30200630
http://europepmc.org/abstract/MED/24211491
http://europepmc.org/abstract/MED/24951259