Custom citation label

Question

I have been trying to cite different publication types using different labels for each. For instance, having the following bib file

\begin{filecontents}{references.bib}

@article{Anonymous:2013,
Author = {Anonymous, Arthur},
Journal = {Somewhere},
Pages = {46-54},
Title = {Arthur's article},
Volume = {25 (2013)},
Year = {2013},
sorttitle = {b}}

@article{Anonymous:2012c,

Author = {Anonymous, Arthur},
Journal = {Somewhere else},
Pages = {6-12},
Title = {Last words},
Volume = {43 (2012)},
Year = {2012},
sorttitle = {c}}

@book{Anonymous:2012a,
Address = {Someplace},
Author = {Anonymous, Arthur},
Publisher = {Nobody},
Title = {Book by Arthur},
Year = {2012},
sorttitle = {a}}

\end{filecontents}

\bibliography{references.bib}

How can I produce a citation list with biblatex as follows:

Books

[B1] A. Anonymous, Book by Arthur, bla bla

Articles

[J2] A. Anonymous, Arthur's article, Somewhere, 2013, bla bla

[J1] A. Anonymous, Last words, Somewhere else, 2012, bla bla

Answer 1

You can easily add a prefix to a numeric/alphabetic label with the labelprefix option to \newrefcontext. labelprefix needs defernumbers enabled globally. The bibliography can be split by type as described in Sectioning bibliography by type of referred item with the type option to \printbibliography.

An entry in a bibliography always applies the current refcontext. Citations apply the last refcontext (last for implementational simplicity) in which an entry was printed in a bibliography

\documentclass[british]{article}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage{babel}
\usepackage{csquotes}

\usepackage[style=numeric, backend=biber, defernumbers]{biblatex}

\addbibresource{biblatex-examples.bib}

\begin{document}
\cite{sigfridsson,worman,baez/article,nussbaum,aksin}

\printbibheading
\newrefcontext[labelprefix=B]
\printbibliography[type=book, title=Books, heading=subbibliography]
\newrefcontext[labelprefix=J]
\printbibliography[type=article, title=Articles, heading=subbibliography]
\end{document}