How to find the ISBN from the DOI? My question is inverse of the following question: 
How can you find the DOI of an article that doesn&#39;t seem to have one?

I am looking for the ISBN number (it's a requirement for getting permissions on copyright.com) for the following paper: 
http://arc.aiaa.org/doi/abs/10.2514/6.2000-519

I found its DOI to be doi:10.2514/6.2000-519 from the citation data, however I couldn't find the ISBN. Is this typical? In the sense that can there be a DOI but not an ISBN for a manuscript?
Articles don't usually have an ISBN since they are for books. It should be sufficient to give the title of the article you are interested in to copyright.com, which is AIAA's preferred mechanism for copyright license clearance. That being said, searching your article's title on copyright.com gives a null result. As such, you should probably contact AIAA directly, or stick a sequence of zeros into copyright.com's extended request form.