# Make citation publishing date appear in square brackets when cited in parentheses

I know there are already an answers to the question How to make citations appear within square brackets [ ] instead of parentheses ( )? but there is something else I'm looking for. When I cite a number of references in a parentheses, I want the publish dates of those references to appear in square brackets. But in any other case in the document I want those citation dates to appear in parentheses. To illustrate the sentence in TeX (for bibliography style I'm using jsb.bst):

\documentclass{article}
\usepackage{natbib}
\begin{document}
Several studies in the past have investigated the perception of emotions from body
movement (e.g. \citet{Dittrich1996, Pollick2001}).
\bibliography{test}
\end{document}.


with simplified bibliography for test.bib

@article{Dittrich1996,
author = {Dittrich, Winand H and Troscianko, Tom and Lea, S E and Morgan, D},
year = {1996}
}
@article{Pollick2001,
author = {Pollick, Frank E. and Paterson, H M and Bruderlin, Armin and Sanford, A J},
year = {2001}
}


produces the following effect:

Several studies in the past have investigated the perception of emotions from body movement (e.g. Dittrich et al. (1996); Pollick et al. (2001)).

which has one parentheses within another - not very neat (and can rise some grammar sensitive eyebrows). Here is what I want:

Several studies in the past have investigated the perception of emotions from body movement (e.g. Dittrich et al. [1996]; Pollick et al. [2001]; Scherer [2003]).

-
It would be a great help for solvers if you could edit your post and add compilable (minimum working) example with bib file included. – Malipivo Apr 11 '14 at 11:30
@Malipivo Ok, fair enough, replicable example provided with link to bibliography style. – Geek On Acid Apr 11 '14 at 12:15
My impression is that you want square brackets everywhere. I can't see why they should change shape depending on the context. Anyway, doing it automatically might be done, but it would definitely be very fragile. – egreg Apr 11 '14 at 12:22
@egreg There is a lot of discussion about parentheses within parentheses (e.g. english.stackexchange.com/questions/28195/double-parentheses) but overall you should use ([]) format. In the context of my question its also an aesthetic choice - I don't like the look of square brackets and its not something you see very often in publication (i.e. you typically see parentheses instead of square brackets). Thats why I don't want square brackets everywhere. – Geek On Acid Apr 11 '14 at 12:32
@GeekOnAcid I see no case like yours in the thread you link, and also in the one linked for duplicate. With my mathematician hat on, I'd say that the parentheses around the year have a semantic function, so they shouldn't be changed. – egreg Apr 11 '14 at 12:38

I recommend you use the command \citealt, not \citealp, for the job at hand. (The instruction will insert a comma between the author and year substrings; I don't think that's what you're looking for.)

\RequirePackage{filecontents}
\documentclass{article}
\begin{filecontents*}{test.bib}
@article{Dittrich1996,
author = {Dittrich, Winand H. and Troscianko, Tom and Lea, S. E. and Morgan, D.},
journal = "XYZ",
volume  = 1,
issue   = 1,
pages   = "1-100",
year = {1996}
}
@article{Pollick2001,
author = {Pollick, Frank E. and Paterson, H M and Bruderlin, Armin and Sanford, A J},
journal = "XYZ",
volume  = 5,
issue   = 1,
pages   = "12-15",
year = {2001}
}
\end{filecontents*}
\usepackage[square]{natbib}
\begin{document}
\bibliographystyle{jmb}
Several studies in the past have investigated the perception of emotions from body
movement (e.g., \citealt{Dittrich1996, Pollick2001}).
\bibliography{test}
\end{document}

-