  An \textit{abstract argumentation framework} ({\sc af} for short) is a
directed graph $(A,R)$ where $A$ is a set of \textit{abstract arguments} and
$R\subseteq A \times A$ is the \textit{attack} relation. Let $H=(A,R)$ be an
{\sc af}, $S \subseteq A$ be a set of arguments and $S^+ = \{y \mid \exists
x\in S \text{ with }(x,y)\in R\}$. Then, $S$ is a \textit{stable extension} in
$H$ if and only if $S^+ = A\setminus S$. In this paper, we present a thorough,
formal validation of a known backtracking algorithm for listing all stable
extensions in a given {\sc af}.
