# Excluding items cited in another .tex file from biblatex bibliography?

Suppose I have two .tex files, each of which must have a bibliography. However, I want the bibliography in the second file to contain only citations that are not in the first. As an example:

\documentclass[11pt, a4paper]{article}

\usepackage[american]{babel}
\usepackage{csquotes}
\usepackage[style=apa,natbib=true,backend=biber,maxbibnames=99,url=false]{biblatex}
\DeclareLanguageMapping{american}{american-apa}

\bibliography{test}

\begin{document}

This is test file 1 \citep{Tversky:Kahneman:1990,Tversky:Kahneman:1974}

\printbibliography

\end{document}


This first file cites two sources.

Here is the second file:

\documentclass[11pt, a4paper]{article}

\usepackage[american]{babel}
\usepackage{csquotes}
\usepackage[style=apa,natbib=true,backend=biber,maxbibnames=99,url=false]{biblatex}
\DeclareLanguageMapping{american}{american-apa}

\bibliography{test}

\begin{document}

This is test file 2 \citep{Tversky:Kahneman:1990,Kahneman:1973}

\printbibliography

\end{document}


Notice that this tex document cites two sources: one that was cited in the first, and one that wasn't. I'd like the reference section here to include only Kahneman:1973, because Tversky:Kahneman:1990 is included in the first.

Here's my test.bib in case you want to compile the files above...

@book{Kahneman:1973,
author = {Kahneman, D.},
title = {Attention and effort},
publisher = {Prentice-Hall},
year = {1973},
confidential = {n}
}

@article{Tversky:Kahneman:1974,
author = {Tversky, A. and Kahneman, D.},
title = {Judgment under Uncertainty: {H}euristics and Biases},
journal = {Science},
year = {1974},
volume = {185},
number = {4157},
pages = {1124-1131},
note = {10.1126/science.185.4157.1124},
confidential = {n}
}

@incollection{Tversky:Kahneman:1990,
author = {Tversky, A. and Kahneman, D.},
title = {Judgements under uncertainty: {H}euristics and Biases},
booktitle = {Rationality in action: {C}ontemporary approaches.},
publisher = {Cambridge University Press},
year = {1990},
pages = {171-188},
editor = {Moser, Paul K.},

Is there a way to accomplish this? I am using latexmk to compile my document. I'm also open to ways of using extra scripting to do it. Thanks!