# natbib with Vancouver bibliography style

I'm write a document of type tufte-handout, and wanted to use Vancouver reference style for bibliography, however I get the following error:

Package natbib Error: Bibliography not compatible with author-year citations.

This doesn't stop the document from generating, and references are also created fine, but they use plane bib style. How can I stop this error from occurring, and what does it actually mean? Is there a way to force Vancouver style?

EDIT: Added MVE. I should also mention I'm using BasicTeX. Minimum working example:

\documentclass{tufte-handout}

\usepackage{lipsum}

\begin{document}

\lipsum[1] \cite{Lucas:2006}

\bibliographystyle{vancouver}
\nobibliography{test-refs}

\end{document}

Content of bib file:

@inbook{Lucas:2006,
Author = {Adam Lucas},
Date-Added = {2016-03-01 22:05:32 +0000},
Date-Modified = {2016-03-01 22:05:32 +0000},
Number = {90-04-14649-0},
Pages = {65},
Publisher = {Brill Publishers},
Title = {Wind, Water, Work: Ancient and Medieval Milling Technology},
Year = {2006}}
• Please show us the exact code with which you load the natbib package and specify the bibliography style. – Mico Mar 1 '16 at 22:03
• @Mico I don't load the natbib myself. However, I've added code for minimum verifiable example. Thanks @egreg :) – user14492 Mar 1 '16 at 22:11

• Using a new example project from ShareLatex, if I set \bibliographystyle{vancouver} and add \setcitestyle{numbers} just after \usepackage{natbib}, I get an error due to the presence of  url={whatever}, in an entry of bib file. – mmj Nov 26 '16 at 10:20