http://europepmc.org/abstract/MED/20601953
http://europepmc.org/abstract/MED/27884971
http://europepmc.org/abstract/MED/27029036
http://europepmc.org/abstract/MED/20724984
http://europepmc.org/abstract/MED/27127180
http://europepmc.org/abstract/MED/24030381
http://europepmc.org/abstract/MED/23099237
http://europepmc.org/abstract/MED/20601954