# Citation from same first author but different year

My problem is the following, I have 2 articles published by the same first author at 2 distinct years in Bibtex that I want to cite within the text in the "author-year" style. Even though I tried re-entering the citations over and over in Bibtex with different cite-key entries, one of the references is appearing in the text as a question mark (?), whereas all remaining references are showing up just fine.

MWE:

\documentclass[preprint,12pt,authoryear]{elsarticle}

\usepackage{natbib}

\biboptions{comma,round}
\biboptions{semicolon}

\begin{document}

[….text………. with following commands for in-text citations: \citep and \citet]

\end{document }


Bib entries:

@article{Ratnayake,
Author = {Ratnayake, W.M.N.,Hansen, StevenL. and Kennedy, MichaelP.},
Journal = {Journal of the American Oil Chemists' Society},
Number = {6},
Pages = {475-488},
Title = {{Evaluation of the CP-Sil 88 and SP-2560 GC Columns Used in the Recently Aapproved AOCS Official Method Ce 1h-05: Determination of cis-, trans-, saturated, monounsaturated, and polyunsaturated fatty acids in vegetable or non-ruminant Animal Oils and Fats by Capillary GLC Method}},
Volume = {83},
Year = {2006}}


This reference is appearing as question mark when cited within text

@inbook{Hernandez,
Author = {W.M. Nimal Ratnayake and Cristina Cruz-Hernandez},
Chapter = {Chapter 5},
Edition = {second edition},
Editor = {Destaillats, Fr{\'e}d{\'e}ric and S{\'e}b{\'e}dio, Jean-Louis and Dionisi, Fabiola and Chardigny, Jean-Michel},
Pages = {105 - 146},
Series = {Oily Press Lipid Library Series},
Title = {Trans Fatty Acids in Human Nutrition (second edition)},
Year = {2012}}


Any feedback is highly appreciated!

• Can you reduce packages until your error disappears? This will improve the minimal not-working example. You can also use the > code formatting for your tex code to improve its formatting. Aug 7, 2014 at 12:34
• Mcwise, thanks for your reply. Could you elaborate a little bit further? I am new to the software and trying my best to make things work. Aug 7, 2014 at 12:44
• Please also post both bib entries, and please which one of the two is giving you problems. Incidentally, there may be a typo on the first line of your code snippet: Is the name of the document class elsarticle or els article?
– Mico
Aug 7, 2014 at 12:45
• @Lollati please post the exact entries copied from the .bib file, and also please use the code formatting on them. Thanks! Welcome to TeX.SX! Aug 7, 2014 at 13:22

The first bib-Entry (Ratnayake) misses an "and" between the first two authors.

And you should have a look at your BibTeX warning:

BibTeX>  Warning-- can't use both author and editor fields in Hernandez


It is explainded here: The idea is that an inbook entry refers to a book entry, and therefore should not have an editor.

\documentclass{article}

\usepackage{natbib}
\usepackage{filecontents}
\begin{filecontents*}{\jobname.bib}

@article{Ratnayake,
Author = {Ratnayake, W.M.N. and Hansen, Steven L. and Kennedy, Michael P.},
Journal = {Journal of the American Oil Chemists' Society},
Number = {6},
Pages = {475-488},
Title = {{Evaluation of the CP-Sil 88 and SP-2560 GC Columns Used in the Recently Aapproved AOCS Official Method Ce 1h-05: Determination of cis-, trans-, saturated, monounsaturated, and polyunsaturated fatty acids in vegetable or non-ruminant Animal Oils  and Fats by Capillary GLC Method}},
Volume = {83},
Year = {2006}}

@book{HernandezBook,
Editor = {Destaillats, Fr{\'e}d{\'e}ric and S{\'e}b{\'e}dio, Jean-Louis and Dionisi, Fabiola and Chardigny, Jean-Michel},
title = {Trans Fatty Acids in Human Nutrition (second edition)},
Series = {Oily Press Lipid Library Series},
Edition = {second edition},
Year = {2012},
volume = {1},
}

@inbook{Hernandez,
Author = {W.M. Nimal Ratnayake and Cristina Cruz-Hernandez},
Chapter = {5},
Pages = {105 - 146},
crossref="HernandezBook",
}

@incollection{RatnayakeCollection,
Author = {Ratnayake, W.M.N. and Cruz-Hernandez, C.},
Booktitle = {Trans Fatty Acids in Human Nutrition},
Pages = {105-146},
Title = {Analysis of Trans Fatty Acids of Partially Hydrogenated Vegetable Oils and Dairy Products},
Year = {2009}
}

\end{filecontents*}

\begin{document}
\nocite{*}
\bibliographystyle{plain}
\bibliography{\jobname}
\end{document}

• Thanks Hackbard. The reference was in the form of an in collection, but still question mark is still popping up in the text. All other references are just fine. I can't seem to know what I am doing wrong Aug 7, 2014 at 18:46
• Would it be possible to enter only this reference manually while keeping Bibtex for the remaining ones? In this case how would it be listed in the references section of the manuscript? Thanks! Aug 7, 2014 at 18:54
• If you edit my post, please make sure, that the formatting stays correct. I updated my post again and included your Ratnayake-incollection-Entry, works without a problem for me. Aug 7, 2014 at 20:50
• @Hackbard_C-- Thanks for your feedback. I followed your suggestion to the letter but it still didn't work, the question mark is still appearing in the text. Aug 8, 2014 at 6:54
• That's strange, as my code at least works fine for me. Please provide a minmal working example, startig with \documentclass and ending with \end{document}, which shows your problem. Aug 8, 2014 at 7:31