> 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.