http://europepmc.org/abstract/MED/22991414
http://europepmc.org/abstract/MED/28481359
http://europepmc.org/abstract/MED/8137263
http://europepmc.org/abstract/MED/7730141
http://europepmc.org/abstract/MED/8569192
http://europepmc.org/abstract/MED/26962861
http://europepmc.org/abstract/MED/28930868