Elsevier Copyrigth Notice

NOTICE: this is the author's version of a work that was accepted for publication in a journal published by Elsevier. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published and available following the following the "DOI" link on the refering page.


Full text pdf.