http://europepmc.org/abstract/MED/9639416
http://europepmc.org/abstract/MED/11301359
http://europepmc.org/abstract/MED/24850867
http://europepmc.org/abstract/MED/27127180
http://europepmc.org/abstract/MED/24030381
http://europepmc.org/abstract/MED/25092778