http://europepmc.org/abstract/MED/20177704
http://europepmc.org/abstract/MED/22420423
http://europepmc.org/abstract/MED/30181556
http://europepmc.org/abstract/MED/27535334
http://europepmc.org/abstract/MED/28481359
http://europepmc.org/abstract/MED/28580595
http://europepmc.org/abstract/MED/22722201
http://europepmc.org/abstract/MED/29349598