
Digital Object Identifier
What 
  is DOI? 
  The digital object identifier (DOI) may be used to cite and link to electronic 
  documents.
  The DOI will never change, which makes it an ideal system for citing your article.
  The DOI scheme is administered by the International DOI Foundation (http://www.doi.org). 
  
  AIDIC as well as many of the world's leading learned publishers have come to 
  build a DOI-based article linking scheme for increasing the visibility of its 
  publications. 
  
The general structure of the DOI number associated to Chemical Engineering Transactions volumes is:

to download the above paper, click : http://dx.doi.org/10.3303/cet0918162
In 
  case you wish to visit the whole content of a volume, set the paper number = 
  000
  
ex: http://dx.doi.org/10.3303/cet0918000
In case you wish to know which volumes have been published in a year, set the volume number = 00