How to split bibliography into “works cited” and “works not cited”?

Question

I need two bib-like sections: a "References" giving works explicitly cited in my text, and a "Bibliography" (or "Further reading" if you prefer) giving everything from my bibfile that didn't already appear in "References". The first is of course completely standard, but the second... I'm stumped.

Further loose constraints: I'm somewhat committed to biblatex and the biblatex-apa style. But I'll happily accept an answer not related to them if there's any chance I can adapt it.

Answer 1

One learns something new about biblatex every day. :-)

\documentclass{article}

\usepackage[defernumbers=true]{biblatex}

\DeclareBibliographyCategory{cited}
\AtEveryCitekey{\addtocategory{cited}{\thefield{entrykey}}}

\usepackage{filecontents}

\begin{filecontents}{\jobname.bib}
@misc{A01,
  author = {Author, A.},
  year = {2001},
  title = {Alpha},
}
@misc{B02,
  author = {Buthor, B.},
  year = {2002},
  title = {Bravo},
}
@misc{C03,
  author = {Cuthor, C.},
  year = {2003},
  title = {Charlie},
}
\end{filecontents}

\addbibresource{\jobname.bib}

\nocite{*}

\begin{document}

Some text \autocite{A01,B02}.

\printbibliography[category=cited]% default title for `article` class: "References"

\printbibliography[title={Further Reading},notcategory=cited]

\end{document}