# Temporarily override biblatex reference options

I am using biblatex-chicago with the option url=false, but I want to include a URL for just a few references. Is there a command that would allow me to reintroduce the URL for just these references while maintaining the universal option?

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Is the situation where you want to remove the URL limited to certain entry types (and if yes, which) or is it random? If it's only for certain types, the situation may be much easier. – Benedikt Bauer Mar 5 '13 at 11:20
It is for a book that is available online. Obviously, using different entry types would work, but I am using citeulike, which does not allow the full-range of bibtex entry types. I am using chromeos, so have no access to JabRef. Hence I just wanted to be able to have a single book entry that includes a url. – David Rowthorn Mar 5 '13 at 12:07
It's not really good style and a bit of abusing of bibtex's fields, but you could just put the URL into the note field if you have it available on citeulike. – Benedikt Bauer Mar 5 '13 at 12:19
The question is, do you want to include the URL for all books, if there is one, and no other entrytypes? – PLK Mar 5 '13 at 12:38
I have since switched to bibsonomy and just resigned myself to the fact that I will have to manually delete urls from papers and books, since doi is preferable anyway. This way, I just add the url to entries that I want to have it in the citation. Not really a proper solution. – David Rowthorn Mar 5 '13 at 16:17

To allow URLs for indiviual references, add an options = {url=true}, field to the respective .bib entries. (For enabling URLs for certain entry types see URL field only for certain reference types with biblatex)

\documentclass{article}

\usepackage[american]{babel}
\usepackage[babel]{csquotes}
\usepackage[url=false,backend=biber]{biblatex-chicago}

\usepackage{filecontents}

\begin{filecontents}{\jobname.bib}
@misc{A01,
author = {Author, A.},
year = {2001},
title = {Alpha},
url = {www.alpha.com},
}
@misc{B02,
author = {Buthor, B.},
year = {2002},
title = {Bravo},
url = {www.bravo.com},
options = {url=true},
}
\end{filecontents}