My pet peeve is with instructors who prevent their students from using anything on ‘the Internet’ as a source for research papers.
Modern public libraries and universities with extensive research facilities frequently pay for the use of online databases. They do this for many reasons including lack of physical space for printed books and journals as well as the enhanced ability to perform searches of digital content. The quality of the material is not related to the form of the content. A book or article should not be given greater confidence simply because it is physical. An electronic article from the Journal of the American Medical Association should not be considered of less value simply because it was obtained over the Internet. Many articles from quality databases are peer reviewed. Many books and magazine articles are not.
Maybe sources for research papers should be restricted to ‘peer reviewed’ articles or ‘first person’.
Consider the source – not the form.