Almost all papers these days have a DOI and it is worth knowing how to use them. At the top or bottom of the first page of a paper, you will see something like this: doi:10.1016/j.csda.2006.07.028 This is a unique and permanent identifier for the paper known as a “Digital Object Identifier”. The part before the forward slash (10.1016 in the example above) identifies the naming authority (in this case Elsevier) and the part after the forward slash …