Store and retrieve content across documents

Question

Possible Duplicate:
Automating quoting across LaTeX documents

I'm working on 2 documents: 1.tex and 2.tex.

2.tex is a metadocument about 1.tex, so that 2.tex has a lot of quotations from 1.tex. Thus, if I modify 1.tex, I need to modify 2.tex to reflect the changes accordingly. Such a procedure, however, is tedious and error-prone.

My question is: how can I store content from 1.tex for later insertion in 2.tex? I was wondering if there is any package like this:

1.tex:

\documentclass{book}
\usepackage{foo}
\begin{document}
First sentence. \StoreAndPrint{<key>}{Second sentence}. Third sentence.
\end{document}

2.tex:

\documentclass{article}
\usepackage{foo}
\begin{document}
The author says:
 \begin{quote}
 \RetrieveAndPrint{<key>}
 \end{quote}
\end{document}

Running $ latex 1, and then $ latex 2, would output an automatically updated 2.dvi.

\input

I could create as many separate tex files as quotations, and then \input them into both documents, but that would make editing 1.tex too hard.