http://europepmc.org/abstract/MED/8683987
http://europepmc.org/abstract/MED/8555068
http://europepmc.org/abstract/MED/7632963
http://europepmc.org/abstract/MED/7882348
http://europepmc.org/abstract/MED/21680795
http://europepmc.org/abstract/MED/8547074
http://europepmc.org/abstract/MED/10090949
http://europepmc.org/abstract/MED/12870051
http://europepmc.org/abstract/MED/8637233
http://europepmc.org/abstract/MED/8665486
http://europepmc.org/abstract/MED/7630199
http://europepmc.org/abstract/MED/7882134
http://europepmc.org/abstract/MED/7606004
http://europepmc.org/abstract/MED/11380395