diff --git a/thesis/chapters/quantum_computing.tex b/thesis/chapters/quantum_computing.tex
index 3a33796..af067d8 100644
--- a/thesis/chapters/quantum_computing.tex
+++ b/thesis/chapters/quantum_computing.tex
@@ -15,8 +15,8 @@
 \end{definition}
 
 A gate acting on a qbit is a unitary operator $G \in U(2)$. One can show that
-$\forall G \in U(2)$ $G$ can be approximated arbitrarily good as a product of unitary generator matrices
-\cite[Chapter 4.3]{kaye_ea2007}\cite[Chapter 2]{marquezino_ea_2019};
+$\forall G \in U(2)$ $G$ can be written as a product of unitary generator matrices
+\cite[Chapter 4.2]{nielsen_chuang_2010}\cite[Chapter 4.3]{kaye_ea2007}\cite[Chapter 2]{marquezino_ea_2019};
 common choices for the generators are $ X, H, R_{\phi}$ or $Z, H, R_{\phi}$ with 
 \label{ref:singleqbitgates}