# How to cite part of online entry (website chapter) in BibLaTex?

I want to cite a part of a web page. Something analogical to a chapter of a book. But from the documentation, the @online entry only has subtitle and titleaddon fields which seem somehow relevant, but from my understanding serve to display a title referencing the whole article, not part of it.

(The website I want to reference.) What I'm currently doing is:

@online{parallel-computing,
author = "Blaise Barney",
title = "Introduction to Parallel Computing",
url = "https://computing.llnl.gov/tutorials/parallel_comp/#Whatis"
}


And I'd like to specifically refer to the part What is Parallel Computing?, which I'm currently referencing with the URL (don't know if that's appropriate).

• I guess you could just use @inbook. It should look OK. Use author, title, booktitle, url, and date. – David Purton Aug 6 at 12:17

For this particular example (and I guess for most website with their own URL) I would just use @online to refer to the complete website and give the 'section' in the postnote of the citation to refer to the specific part. Much like one normally adds the complete @book to the bibliography, but only cites a specific page.

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

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

\usepackage{filecontents}
\begin{filecontents}{\jobname.bib}
@online{parallel-computing,
author       = {Blaise Barney},
title        = {Introduction to Parallel Computing},
url          = {https://computing.llnl.gov/tutorials/parallel_comp},
urldate      = {2019-08-06},
organization = {Lawrence Livermore National Laboratory},
}
\end{filecontents}

\begin{document}
Lorem ipsum \autocite[section \enquote{What is Parallel Computing?}]{parallel-computing}.
\printbibliography
\end{document}


To me the most natural, self-contained unit in this case just appears to be the complete website.

If you insist that the specific section be referenced in the bibliography, you can follow David Purton's advice from the comments and (ab)use the @inbook entry type.

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

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

\usepackage{filecontents}
\begin{filecontents}{\jobname.bib}
@inbook{barney:whatis,
author       = {Blaise Barney},
booktitle    = {Introduction to Parallel Computing},
title        = {What is Parallel Computing?},
url          = {https://computing.llnl.gov/tutorials/parallel_comp/#Whatis},
urldate      = {2019-08-06},
publisher    = {Lawrence Livermore National Laboratory},
}
\end{filecontents}

\begin{document}
Lorem ipsum \autocite{barney:whatis}.
\printbibliography
\end{document}


Of course it would be possible to define a new entry type called @inonline that relates to @online as @inbook relates to @book. At the moment I doubt this is worth the effort, but it is most certainly doable. See How can I create entirely new data types with BibLaTeX/Biber? for a starter.

Alternatively, Bib Formatting Question shows how you could add maintitle to @online entries so that you could have something like

@online{barney:whatis,
author       = {Blaise Barney},
maintitle    = {Introduction to Parallel Computing},
title        = {What is Parallel Computing?},
url          = {https://computing.llnl.gov/tutorials/parallel_comp/#Whatis},
urldate      = {2019-08-06},
organization = {Lawrence Livermore National Laboratory},
}

• That's a pretty exhaustive yet comprehensible answer. I'll now (ab)use the comments section by saying thank you for that. – h4nek Aug 7 at 19:14