http://europepmc.org/abstract/MED/29681454
http://europepmc.org/abstract/MED/7615358
http://europepmc.org/abstract/MED/26317919
http://europepmc.org/abstract/MED/1312896
http://europepmc.org/abstract/MED/10091733
http://europepmc.org/abstract/MED/15073856
http://europepmc.org/abstract/MED/8242638
http://europepmc.org/abstract/MED/7767998
http://europepmc.org/abstract/MED/17001163
http://europepmc.org/abstract/MED/17473653