http://europepmc.org/abstract/MED/10348818
http://europepmc.org/abstract/MED/10874665
http://europepmc.org/abstract/MED/21573592
http://europepmc.org/abstract/MED/8495424
http://europepmc.org/abstract/MED/12796400
http://europepmc.org/abstract/MED/15363320