Sstrhsrtj

I have a main document and I am using the natbib package to handle my bibtex database.
Here is my bottom part of the document displaying the bibliography code

...

backmatter

nocite{*}

bibliographystyle{plainnat}

bibliography{mybiblifile}

end{document}

This is the bottom part of my code and it seems pretty normal.
When I typeset everything after several runs of BibTeX, I get this error message:

Misplaced alignment tab character &. You have placed an alignment tab character '&' in the wrong place. If you want to align something, you must write it inside an align environment such as begin{align} … end{align}, begin{tabular} … end{tabular}, etc. If you want to write an ampersand '&' in text, you must write & instead.

Now I am opening the bibliography file mybiblifile.bib, one entry draws my attention.

@INPROCEEDINGS{frenkel_fine_2013,

title = {Fine temperature measurement and fabrication of on-chip whispering-gallery mode micro-sensors},

url = {http://proxy.library.nyu.edu/login?url=http://search.ebscohost.com/login.aspx?direct=true&db=edselc&AN=edselc.2-52.0-84901804547&site=eds-live},

doi = {10.1115/MNHMT2013-22003},

booktitle = {{ASME} 2013 4th {International} {Conference} on {Micro}/{Nanoscale} {Heat} and {Mass} {Transfer}, {MNHMT} 2013},

publisher = {American Society of Mechanical Engineers (ASME)},

author = {Frenkel, M. and Avellan, M. and Guo, Z.},

year = {2013},

note = {Conference Proceedings}

}

I realized that it is the & characters inside the URL entry of the Bibtex that causes the problem. When I delete these characters from the URL entry, the typesetting works fine and no more error messages appear.

How do we deal with this problem?

You did not show us a complete MWE, showing your used documentclass and used packages. Please next time show a complete MWE, not only code snippets ...

It seems you miised to call package hyperref (this packages calls url internaly) or if you do not use hyperref you should call package url or xurl.

See the following MWE (package filecontents is only used to have bib file and tex code together in a MWE):

RequirePackage{filecontents}

begin{filecontents*}{jobname.bib}

@INPROCEEDINGS{frenkel_fine_2013,

  title = {Fine temperature measurement and fabrication of on-chip whispering-gallery mode micro-sensors},

  url = {http://proxy.library.nyu.edu/login?url=http://search.ebscohost.com/login.aspx?direct=true&db=edselc&AN=edselc.2-52.0-84901804547&site=eds-live},

  doi = {10.1115/MNHMT2013-22003},

  booktitle = {{ASME} 2013 4th {International} {Conference} on {Micro}/{Nanoscale} {Heat} and {Mass} {Transfer}, {MNHMT} 2013},

  publisher = {American Society of Mechanical Engineers (ASME)},

  author = {Frenkel, M. and Avellan, M. and Guo, Z.},

  year = {2013},

  note = {Conference Proceedings}

}

end{filecontents*}





documentclass[10pt,a4paper]{article}



usepackage{natbib}

%usepackage{xurl}

usepackage{hyperref}





begin{document}



nocite{*} % to test all bib entrys

bibliographystyle{plainnat}

bibliography{jobname}



end{document}

and its result without error messages:

If you do not like the empty space at the end of one line you can uncommment line

usepackage{xurl}

in my given MWE.