Is it possible to have headings inside thebibliography? I need to categorize the references into, say, "required" and "optional".
I tried simply putting some text in between \bibitems, but the compiler complains about encountering text not part of a \bibitem.
A solution not involving BibTeX is preferred for now, I'm still learning LaTeX and for the paper I'm writing I only have a handful of references (and not that much time, surprise-surprise :-). I plan to learn BibTeX in the future, of course.
Just before posting I looked at How do I break up a bibliography into separately numbered sections? and one of the answers was mentioning multibib which appears to have such functionality. I'll ask anyway in case there are other solutions, I just need some extra text displayed, not to really break the bibliography into subbibliographies.

