0147-6513/ © 2018 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY-NC-ND license 
(http://creativecommons.org/licenses/BY-NC-ND/4.0/)
Bestelakorik adierazi ezean, itemaren baimena horrela deskribatzen da:0147-6513/ © 2018 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/BY-NC-ND/4.0/)