\begin{thebibliography}{16}
\newcommand{\enquote}[1]{``#1''}
\providecommand{\natexlab}[1]{#1}
\providecommand{\url}[1]{\texttt{#1}}
\providecommand{\urlprefix}{URL }
\expandafter\ifx\csname urlstyle\endcsname\relax
  \providecommand{\doi}[1]{doi:\discretionary{}{}{}#1}\else
  \providecommand{\doi}{doi:\discretionary{}{}{}\begingroup
  \urlstyle{rm}\Url}\fi
\providecommand{\eprint}[2][]{\url{#2}}

\bibitem[{Armstrong(2009)}]{fts}
Armstrong W (2009).
\newblock \emph{\pkg{fts}: \proglang{R} Interface to \pkg{tslib} (A Time Series
  Library in C++)}.
\newblock R package version 0.7.6,
  \urlprefix\url{http://CRAN.R-project.org/package=fts}.

\bibitem[{Colebourne and O'Neill(2010)}]{jodatime}
Colebourne S, O'Neill BS (2010).
\newblock \enquote{\pkg{Joda-Time} -- \proglang{Java} Date and Time API.}
\newblock Release~1.6.2, \urlprefix\url{http://joda-time.sourceforge.net/}.

\bibitem[{Fowler(1997)}]{fowler}
Fowler M (1997).
\newblock \enquote{Recurring Events for Calendars.}
\newblock \emph{Technical report}.

\bibitem[{Garland(2011)}]{boost}
Garland J (2011).
\newblock \enquote{\pkg{Boost.Date$\_$Time} -- \proglang{C++} library.}
\newblock Release~1.46.1, \urlprefix\url{http://www.boost.org/}.

\bibitem[{Grothendieck and Petzoldt(2004)}]{Rnews}
Grothendieck G, Petzoldt T (2004).
\newblock \enquote{Date and Time Classes in \proglang{R}.}
\newblock \emph{R News}, \textbf{4}(1), 32.

\bibitem[{Hallman(2010)}]{tis}
Hallman J (2010).
\newblock \emph{\pkg{tis}: Time Indexes and Time Indexed Series}.
\newblock R package version 1.12,
  \urlprefix\url{http://CRAN.R-project.org/package=tis}.

\bibitem[{James and Hornik(2010)}]{chron}
James D, Hornik K (2010).
\newblock \emph{\pkg{chron}: Chronological Objects which Can Handle Dates and
  Times}.
\newblock R package version 2.3-35. S original by David James, R port by Kurt
  Hornik., \urlprefix\url{http://CRAN.R-project.org/package=chron}.

\bibitem[{Lipper(2008)}]{runts}
Lipper M (2008).
\newblock \enquote{\pkg{runt} -- \proglang{Ruby} Temporal Expressions.}
\newblock Release~0.7.0, \urlprefix\url{http://runt.rubyforge.org/}.

\bibitem[{Parker(2010)}]{bball}
Parker RJ (2010).
\newblock \enquote{Basketball Geek: Advancing Our Understanding of the Game of
  Basketball.}
\newblock \urlprefix\url{http://www.basketballgeek.com/data/}.

\bibitem[{{Portfolio and Risk Advisory Group, Commerzbank
  Securities}(2009)}]{its}
{Portfolio and Risk Advisory Group, Commerzbank Securities} (2009).
\newblock \emph{\pkg{its}: Irregular Time Series}.
\newblock R package version 1.1.8,
  \urlprefix\url{http://CRAN.R-project.org/package=its}.

\bibitem[{{R Development Core Team}(2010)}]{R}
{R Development Core Team} (2010).
\newblock \emph{\proglang{R}: A Language and Environment for Statistical
  Computing}.
\newblock R Foundation for Statistical Computing, Vienna, Austria.
\newblock {ISBN} 3-900051-07-0, \urlprefix\url{http://www.R-project.org}.

\bibitem[{Ryan and Ulrich(2010)}]{xts}
Ryan JA, Ulrich JM (2010).
\newblock \emph{\pkg{xts}: Extensible Time Series}.
\newblock R package version 0.7-1,
  \urlprefix\url{http://CRAN.R-project.org/package=xts}.

\bibitem[{Trapletti and Hornik(2009)}]{tseries}
Trapletti A, Hornik K (2009).
\newblock \emph{\pkg{tseries}: Time Series Analysis and Computational Finance}.
\newblock R package version 0.10-22.,
  \urlprefix\url{http://CRAN.R-project.org/package=tseries}.

\bibitem[{Wickham(2009)}]{ggplot2}
Wickham H (2009).
\newblock \emph{\pkg{ggplot2}: Elegant Graphics for Data Analysis}.
\newblock Springer New York.
\newblock ISBN 978-0-387-98140-6.
\newblock \urlprefix\url{http://had.co.nz/ggplot2/book}.

\bibitem[{Wuertz and Chalabi(2010)}]{timeSeries}
Wuertz D, Chalabi Y (2010).
\newblock \emph{\pkg{timeSeries}: Rmetrics - Financial Time Series Objects}.
\newblock R package version 2110.87,
  \urlprefix\url{http://CRAN.R-project.org/package=timeSeries}.

\bibitem[{Zeileis and Grothendieck(2005)}]{zoo}
Zeileis A, Grothendieck G (2005).
\newblock \enquote{\pkg{zoo}: S3 Infrastructure for Regular and Irregular Time
  Series.}
\newblock \emph{Journal of Statistical Software}, \textbf{14}(6), 1--27.
\newblock \urlprefix\url{https://www.jstatsoft.org/v14/i06/}.

\end{thebibliography}
