deletions | additions       diff --git a/header.tex b/header.tex  index a0da61c..2a766b6 100644  --- a/header.tex  +++ b/header.tex 
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\usepackage[version=3]{mhchem}   \usepackage[separate-uncertainty]{siunitx}  \usepackage{natbib}  \bibliographystyle{plainnat}