BibLatex: two bibliographies with roman and arabic numbering

Question

The answer to Jannik's question (Biblatex: Two bibliographies with different styles and sortings) is almost what I like to have. But instead of style=alphabetic I would like to use style=phys and have bolded roman numerals as labels in the first bibliography and corresponding in-text citations. (i.e. replace [Bbb02] with {\bf I} and [Aaa03] with {\bf II} and get them in the order of existence in the bibliography.)

Answer 1

This is actually quite a bit easier than Biblatex: Two bibliographies with different styles and sortings That is because we only want to mix numeric styles and we don't need to change the sorting.

\documentclass{article}

\usepackage{filecontents}

\begin{filecontents}{biblatextest1.bib}
@BOOK{BookA03,
  author    = {Author Aaa},
  title     = {Some Title},
  publisher = {Some Publisher},
  year      = 2003,
}
@BOOK{BookB02,
  author    = {Author Bbb},
  title     = {Some Title},
  publisher = {Some Publisher},
  year      = 2002,
}
\end{filecontents}

\begin{filecontents}{biblatextest2.bib}
@MISC{LinkC04,
  author  = {Author Ccc},  
  title   = {Some Title},
  year    = 2004,
  url     = {www.test1.com/bild.jpg},
}
@MISC{LinkD01,
  author  = {Author Ddd},
  title   = {Some Title},
  year    = 2001,
  url     = {www.test2.com/bild.jpg},
}
\end{filecontents}

\usepackage[style = phys, defernumbers = true,  backend = biber]{biblatex}
\addbibresource{biblatextest1.bib}
\addbibresource{biblatextest2.bib}

\usepackage{hyperref}

%Append keywords to identify different bibliography entries.
\DeclareSourcemap{
  \maps[datatype=bibtex, overwrite]{
    \map{
      \perdatasource{biblatextest1.bib}
      \step[fieldset=KEYWORDS, fieldvalue=primary, append]
    }
    \map{
      \perdatasource{biblatextest2.bib}
      \step[fieldset=KEYWORDS, fieldvalue=secondary, append]
    }
  }
}

\DeclareFieldFormat{labelnumber}{\ifkeyword{secondary}{#1}{\mkbibbold{\RN{#1}}}}

\begin{document}

The first two citations \cite{LinkD01} and \cite{BookB02}. 
The others are \cite{LinkC04} and \cite{BookA03}.

\printbibliography[title=Bibliography, keyword=primary]
\printbibliography[title=References, keyword=secondary, resetnumbers]
\end{document}

There are more elegant ways to split bibliographies if you do not already have them in different .bib files. But that depends on your setup.