http://europepmc.org/abstract/MED/26617880
http://europepmc.org/abstract/MED/23417712
http://europepmc.org/abstract/MED/22528790
http://europepmc.org/abstract/MED/28874004
http://europepmc.org/abstract/MED/21717448
http://europepmc.org/abstract/MED/23330999
http://europepmc.org/abstract/MED/28236063
http://europepmc.org/abstract/MED/29527387
http://europepmc.org/abstract/MED/22772731
http://europepmc.org/abstract/MED/29615461
http://europepmc.org/abstract/MED/26919320
http://europepmc.org/abstract/MED/23600211
http://europepmc.org/abstract/MED/24460285
http://europepmc.org/abstract/MED/24532263
http://europepmc.org/abstract/MED/23840696