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Citing other papers is easy. Voilà: \cite{2012} or \cite{Holstein_2009}. Click on the \verb|+| (plus) button in the toolbar to search articles and cite them. Authorea also comes with a powerful commenting system \cite{25683567}. \cite{Berg_2010}Don't agree that $E = mc^{3}$ mc^{2}$  ?!? Highlight the text you want to discuss or click the comment button. Find out more about using Authorea on \href{https://www.authorea.com/help}{our help page}. This is how you add a citation \cite{25681375} . Cool \cite{Malishev_2015}. Two people can edit different blocks at once, but not the same same\cite{Rayner_2010}  one.