> Short of linking to full-text, which is not going to happen for anything published after 1928 (except for purchased content, in the case of more recent materials),
I think you meant short of:
* Government documents and many intergovernmental documents
* Open access documents and journals
* Most PhD and Masters Theses
* Orphan works where someone has been bold
* A wide range of philanthropically funded works, particularly in education
For a non-trivial number of researchers, that's most of their sources.