http://europepmc.org/abstract/MED/24986214
http://europepmc.org/abstract/MED/23222489
http://europepmc.org/abstract/MED/28592321
http://europepmc.org/abstract/MED/23132392
http://europepmc.org/abstract/MED/24196187
http://europepmc.org/abstract/MED/23225304