http://europepmc.org/abstract/MED/12417040
http://europepmc.org/abstract/MED/8938142
http://europepmc.org/abstract/MED/22327622
http://europepmc.org/abstract/MED/29681454
http://europepmc.org/abstract/MED/28481359
http://europepmc.org/abstract/MED/9355981
http://europepmc.org/abstract/MED/24956168
http://europepmc.org/abstract/MED/7700630
http://europepmc.org/abstract/MED/11280771
http://europepmc.org/abstract/MED/19375815
http://europepmc.org/abstract/MED/8589032
http://europepmc.org/abstract/MED/7478613
http://europepmc.org/abstract/MED/27528220