http://europepmc.org/abstract/MED/27884971
http://europepmc.org/abstract/MED/27029036
http://europepmc.org/abstract/MED/20520634
http://europepmc.org/abstract/MED/17910630
http://europepmc.org/abstract/MED/24523240
http://europepmc.org/abstract/MED/24850867
http://europepmc.org/abstract/MED/27127180
http://europepmc.org/abstract/MED/24030381