1 files changed, 1 insertions, 1 deletions
diff --git a/doc/documentation.tex b/doc/documentation.tex
index 0de53c7..45727f0 100644
--- a/doc/documentation.tex
+++ b/doc/documentation.tex
@@ -194,7 +194,7 @@ The gauge can be set to the Kerr lapse and shift with the parameters
 in which case the formulas
 \begin{eqnarray}
   \alpha & = &\sqrt{\frac{\Delta}{p^2}}, \\
-  \beta^\phi & = & -2 m r_k a / p^2,
+  \beta^\phi & = & -2 m r_k a / (p^2 \Sigma),
 \end{eqnarray}
 where
 \begin{equation}