Els següents fitxers sobre la llicència estan associats a aquest element:

© 2018 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license 
(http://creativecommons.org/licenses/BY/4.0/)
Except where otherwise noted, this item's license is described as © 2018 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/BY/4.0/)