http://europepmc.org/abstract/MED/20678218
http://europepmc.org/abstract/MED/23996483
http://europepmc.org/abstract/MED/14615365
http://europepmc.org/abstract/MED/20520634
http://europepmc.org/abstract/MED/24523240
http://europepmc.org/abstract/MED/21294243
http://europepmc.org/abstract/MED/24127063
http://europepmc.org/abstract/MED/24850867
http://europepmc.org/abstract/MED/27127180
http://europepmc.org/abstract/MED/24030381
http://europepmc.org/abstract/MED/24608733
http://europepmc.org/abstract/MED/21909114
http://europepmc.org/abstract/MED/23443343