Obscure material unavailable
originally submitted by Arthur Barys:
I sometimes need to find of fiction that are so obscure as to render them worthless to the book marketplace. These titles are out of print, so the only way to find them would be if they were posted in electronic form, e.g. Project Gutenberg. Unfortunately, AFAIK, current copyright law makes this impossible if the work is sufficiently "new".
Stifled uses
Arthur Barys:
Use information found in given works as examples in academic papers.