I haven't dug into the details of the paper yet, but I want to commend the authors for 1.) making it possible to actually download the PDF and 2.) giving some indication, within the actual document, when the paper was published. I'm being a little bit snarky, but I'm very sincere in thanking them.
It's usually not that the authors don't want to provide PDFs but with scientific journals you're often asked to sign a form that transfers the copyrights to the journal. In other words, you're not allowed to make the paper available even though you're the author.
In my experience, finding out when a paper was published is often not too difficult. In most cases, Google makes it easy to find the Journal issue and/or the conference proceedings of the paper. Or you find some third paper that contains a reference with date information that you can then use to double check.
