# Bibliography entries causing Missing }/$inserted and Extra }, or forgotten$ errors

I am using Overleaf, and when I copied and pasted bibliography from a different project into a new one, I am getting errors and cannot figure out what's wrong. The errors I am getting are all Missing } inserted., Missing $inserted. or Extra }, or forgotten$. They refer to some lines in the output.bbl file.

My attempt so far: I manually went through process of elimination and narrowed it down to 4 problematic entries. I checked for underscores _ but they are all in the DOI/URL fields, and I tried checking for missing braces }. When I add this new bibliography, I get the errors. I tried adding each of these one by one and they all individually cause errors. I noticed that all of these are @incollection entries.

@incollection{old-nsf-proposal-1,
doi = {10.1007/978-3-319-20681-3_29},
url = {https://doi.org/10.1007/978-3-319-20681-3_29},
year = {2015},
publisher = {Springer International Publishing},
pages = {307--318},
author = {Nicoletta Adamo-Villani and Ronnie B. Wilbur},
title = {{ASL}-Pro: American Sign Language Animation with Prosodic Elements},
}

@incollection{old-nsf-proposal-44,
doi = {10.1007/978-3-642-31534-3_32},
url = {https://doi.org/10.1007/978-3-642-31534-3_32},
year = {2012},
publisher = {Springer Berlin Heidelberg},
pages = {205--212},
author = {Eleni Efthimiou and Stavroula-Evita Fotinea and Thomas Hanke and John Glauert and Richard Bowden and Annelies Braffort and Christophe Collet and Petros Maragos and Fran{\c{c}}ois Lefebvre-Albaret},
title = {The Dicta-Sign Wiki: Enabling Web Communication for the Deaf},
booktitle = {Lecture Notes in Computer Science}
}

@incollection{old-nsf-proposal-45,
doi = {10.1007/978-3-642-02707-9_3},
url = {https://doi.org/10.1007/978-3-642-02707-9_3},
year = {2009},
publisher = {Springer Berlin Heidelberg},
pages = {21--30},
author = {Eleni Efthimiou and Stavroula-Evita Fotinea and Christian Vogler and Thomas Hanke and John Glauert and Richard Bowden and Annelies Braffort and Christophe Collet and Petros Maragos and J{\'{e}}r{\'{e}}mie Segouat},
title = {Sign Language Recognition,  Generation,  and Modelling: A Research Effort with Applications in Deaf Communication},
booktitle = {Universal Access in Human-Computer Interaction. Addressing Diversity}
}

@incollection{old-nsf-proposal-46,
doi = {10.1007/978-3-319-20681-3_33},
url = {https://doi.org/10.1007/978-3-319-20681-3_33},
year = {2015},
publisher = {Springer International Publishing},
pages = {351--361},
author = {Eleni Efthimiou and Stavroula-Evita Fotinea and Theodore Goulas and Panos Kakoulidis},
title = {User Friendly Interfaces for Sign Retrieval and Sign Synthesis},
}


I checked the .bst file that I have, searched for inproceedings and I found this:

FUNCTION { incollection }
{
output.bibitem
format.authors "author" output.check
new.block
format.articletitle "title" output.check
new.block
crossref missing${ format.in.ed.booktitle "booktitle" output.check new.sentence % jtb: start a new sentence for series/volume format.bvolume output format.number.series output new.sentence publisher "publisher" output.check address "address" output.check % jtb: require address format.bookpages output format.chapter.pages output % gnp - was special.output.nonnull % left out comma before page numbers % jtb: moved from before publisher } { format.incoll.inproc.crossref output.nonnull format.chapter.pages output } if$
fin.block
output.issue.doi.coden.isxn.lccn.url.note
fin.entry
}

FUNCTION { inproceedings }
{
output.bibitem
format.authors "author" output.check
new.block
format.articletitle "title" output.check
howpublished output.dot.space
crossref missing${ journal missing$          % jtb: proceedings appearing in journals
{ format.in.emphasize.booktitle "booktitle"  output.check.dot.space
format.series output.removenospace
format.editors.fml output % BV 2011/09/27 Moved dot to comma
format.bvolume.noseries output
new.sentence
organization output
publisher "publisher" output.check % jtb: require publisher (?)
format.bookpages output
}
{
format.in.booktitle format.city "booktitle" output.check
format.editors.fml output
new.sentence
format.journal.volume.number.day.month.year output
}
if$format.articleno output format.pages.check.without.articleno output } { format.incoll.inproc.crossref output.nonnull format.articleno output format.pages.check.without.articleno output } if$
format.articleno.numpages output
fin.block
output.issue.doi.coden.isxn.lccn.url.note
fin.entry
}


EDIT: added MWE to reproduce error:

SIGCHI-Reference-Format.bst : https://controlc.com/6d1ed4fb

.tex file:

\begin{filecontents*}{bib.bib}
@incollection{old-nsf-proposal-1,
doi = {10.1007/978-3-319-20681-3_29},
url = {https://doi.org/10.1007/978-3-319-20681-3_29},
year = {2015},
publisher = {Springer International Publishing},
pages = {307--318},
author = {Nicoletta Adamo-Villani and Ronnie B. Wilbur},
title = {{ASL}-Pro: American Sign Language Animation with Prosodic Elements},
}
\end{filecontents*}

\documentclass[letterpaper, 11pt, oneside, openright, draft]{book}

\usepackage{url}

% https://tex.stackexchange.com/questions/3033/forcing-linebreaks-in-url
\hypersetup{%
pdfdisplaydoctitle=true, % For Accessibility
pdfstartview={FitH}, % https://tex.stackexchange.com/questions/3450/make-pdf-open-in-fill-window-mode-with-hyperref/7251
pdflang={en},
extension=pdf,
plainpages=false,
pdfpagelayout=SinglePage,
bookmarksnumbered,
hypertexnames=true,
citecolor=blue, % TODO change to black for final version (this makes it easy to check for unfinished links
filecolor=blue, % TODO change to black for final version (this makes it easy to check for unfinished links
linkcolor=blue, % TODO change to black for final version (this makes it easy to check for unfinished links
urlcolor=blue,
final % to avoid draft mode for hyperref
}

\usepackage{doi} % this must be loaded AFTER hyperref!

\begin{document}

Testing... Citing \cite{old-nsf-proposal-1}.

\bibliographystyle{SIGCHI-Reference-Format}
\bibliography{bib}

\end{document}

• Most BibTeX styles that support a doi or url field can interface with the url or hyperref packages in such a way that (normally unsafe) characters like _, \$ and % work as expected without escaping. It is possible that this only works if you load \usepackage{hyperref} in your preamble as the style may fall back to a more primitive command otherwise. But it is also possible that your style does something else entirely. The code snippet of the .bst file shown here is not really helpful to investigate this. ... Feb 15 at 7:07
• ... Please prepare a complete example document (a .tex file citing a problematic entry) that reproduces the problem with as little code as possible. If the .bst file is not available on CTAN, please share a link so we can get hold of the file as well. Feb 15 at 7:08
• you hav not shown the relevant code, the important thing is how it is formatting url fieldsm if it just makes them normal text the_ will give errors. You could show the generated bbl file. Feb 15 at 12:37
• @DavidCarlisle would only the .bbl file "header" and the \bibitem of the problematic entry suffice? I am not experienced with bibliography styles and behind-the-scenes stuff.. Feb 15 at 16:31
• I googled the file name and at first found github.com/seocam/cscw-spb/blob/master/… (which does not appear official), then I omitted the .bst and found chi2020.acm.org/authors/chi-proceedings-format where you can download a template including a SIGCHI-Reference-Format.bst. Unless you have a very good reason to use this specific file, I'd probably stick to a more standard style. Feb 15 at 19:38

What I ended up doing: I could not find a good source for the SIGCHI-Reference-Format.bst file online, so I changed it to the ACM-Reference-Format.bst from CTAN here.
For reference, I have created a diffchecker link to compare the version of SIGCHI-Reference-Format.bst I had (18 January 2012) with the current version of the ACM-Reference-Format.bst (at time of writing, 14 June 2017): https://www.diffchecker.com/m8087Izb
To use the ACM-Reference-Format.bst file, I had to add \usepackage{natbib} to my preamble. I also added \setcitestyle{numbers,square} to use numbers enclosed in square brackets.