http://europepmc.org/abstract/MED/25695693
http://europepmc.org/abstract/MED/28481359
http://europepmc.org/abstract/MED/24797764
http://europepmc.org/abstract/MED/12114798
http://europepmc.org/abstract/MED/26315110
http://europepmc.org/abstract/MED/9033644