# Biblatex urldate - how to change parenthesis with square brackets

I would like to produce a Reference list for online resource that ends with angular brackets for urldate. For example, I would like to have the following example end with "[Accessed 1st Apr. 2016]".

Here is the minimal working example:

\documentclass[12pt,a4paper]{article}
\usepackage[latin1]{inputenc}
\usepackage[british]{babel}
\usepackage[left=2.00cm, right=2.00cm, top=2.00cm, bottom=2.00cm]{geometry}
\usepackage[backend=biber, citestyle=authoryear-ibid,bibstyle=authoryear, sorting=nty, urldate=long]{biblatex}
\DefineBibliographyStrings{english}{urlseen = {Accessed }
}
\usepackage{filecontents}
\begin{filecontents}{references.bib}
@online{Jerald,
author = {Craig D. Jerald},
title = {School culture:'The hidden curriculum'},
year = {2006},
url = {<http://files.eric.ed.gov/fulltext/ED495013.pdf>},
organization = {The Center for Comprehensive School Reform and            Improvement},
urldate = {2016-04-01},
}
\end{filecontents}

\begin{document}

Some statement \parencite{Jerald}.

\printbibliography[title={References}]
\end{document}


By browsing this site I got the information I need to tweak the following:

\DeclareFieldFormat{urldate}{\mkbibparens{\bibstring{urlseen}\space#1}}


It seems that I should replace \mkbibparens with a string that would specify square brackets, but I don't know what string that would be. I should emphasize that I don't want to change brackets style for year of publication or any other usage, just tweak the urldate presentation.

• You seem to be looking for \mkbibbrackets. Note that in the title field of your example you are probably missing a space after the colon and that the URL as given in the url field should not contain the additional < and > characters, if you want angular brackets around the URL then there are other ways to do that. – moewe Apr 3 '16 at 14:37
• BTW citestyle=authoryear-ibid,bibstyle=authoryear could be shortened to the completely equivalent, but easier-to-parse style=authoryear-ibid. – moewe Apr 3 '16 at 14:45
• That works! I've fixed the other points you have noted and that works as well. Thanks. – Niko Z. Apr 4 '16 at 0:14

You can get (context sensitive) square brackets with \mkbibbrackets. It is the equivalent of \mkbibparens and switches the used brackets according to the nesting level.

\documentclass[12pt,a4paper]{article}
\usepackage[utf8]{inputenc}
\usepackage[british]{babel}
\usepackage[backend=biber, style=authoryear-ibid, urldate=long]{biblatex}

\DeclareFieldFormat{urldate}{\mkbibbrackets{\bibstring{urlseen}\space#1}}

\DefineBibliographyStrings{english}{
urlseen = {Accessed}
}

\usepackage{filecontents}
\begin{filecontents}{\jobname.bib}
@online{Jerald,
author       = {Craig D. Jerald},
title        = {School culture: 'The hidden curriculum'},
year         = {2006},
url          = {http://files.eric.ed.gov/fulltext/ED495013.pdf},
organization = {The Center for Comprehensive School Reform and Improvement},
urldate      = {2016-04-01},
}
\end{filecontents}