Update resources.tex

Author: yiannis-had

content/methods/proofs/resources.tex

@@ -28,7 +28,7 @@ \section{Other Resources}
 internet; e.g.,
 \href{https://math.berkeley.edu/~hutching/teach/proofs.pdf}{``Introduction
   to Mathematical Arguments''} \citep{Hutchings2003} and
-\href{http://http://eugeniacheng.com/wp-content/uploads/2017/02/cheng-proofguide.pdf}{``How to
+\href{https://eugeniacheng.com/wp-content/uploads/2017/02/cheng-proofguide.pdf}{``How to
   write proofs''} \citep{Cheng2004}.
 
 \subsection{Motivational Videos}