http://europepmc.org/abstract/MED/12697903
http://europepmc.org/abstract/MED/10706620
http://europepmc.org/abstract/MED/24682267
http://europepmc.org/abstract/MED/24145436
http://europepmc.org/abstract/MED/23407552
http://europepmc.org/abstract/MED/16461462