\documentclass[fleqn,leqno]{article}
\usepackage{hypertlabook}
\pdftitle{ASCII Text}
\fixverbatim
\begin{popup}
\begin{verbatim*}
THEOREM GCD1 == \A m \in Nat \ {0} : GCD(m, m) = m

THEOREM GCD2 == \A m, n \in Nat \ {0} : GCD(m, n) = GCD(n, m)

THEOREM GCD3 == \A m, n \in Nat \ {0} : 
                     (n > m) => (GCD(m, n) = GCD(m, n-m))
\end{verbatim*}
\end{popup}
\makeasciipopup