Citation from same first author but different year

Question

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},
    Publisher = {Woodhead Publishing},
    Series = {Oily Press Lipid Library Series},
    Title = {Trans Fatty Acids in Human Nutrition (second edition)},
    Year = {2012}}

Any feedback is highly appreciated!

Answer 1

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)},
Publisher = {Woodhead Publishing},
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},
Publisher = {Woodhead Publishing},
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}