I had a phone call from a student today who needed a DOI number for an article being used. I had never heard of this before, and had no idea how to access it at all, particularly from our databases. I think our nursing students have to use it pretty often. I muddled through enough to get the number from another source, however, I thought it might be useful if someone who had the knowledge could explain exactly how to locate the number and whether or not the number is specific to the article only, or to the article and the place that is holding it. Or am I the only one who doesn't know?