When I am at home and looking for journal articles I often find article PDFs through google that have been uploaded to various websites (e.g., universities, institutions, arbitrary websites, etc...).
I am worried that using these files may infringe copyright since these articles may be bought by these universities (for example) and (by mistake?) were freely uploaded to their domain name like: www.university.edu.lb/journal_article1.pdf (probably for their own students?).
- Is it ethical to use these downloaded PDFs during my research without going back to my own university elibrary to use them?
- When, if ever, would I be breaching copyright or breaching professional ethics if I accessed these files?
EDIT: my question also covers books as, sometimes, these are entirely available on some sites (whether they are institutional sites or not).