diff --git a/src/BioHelpers_FABER/rmsd.py b/src/BioHelpers_FABER/rmsd.py
index d0d6ed55f5a0d959275aa15b3a2b90e2928c928e..b1b7d9e919944834d01f8e8ac7f71fa878f933e4 100644
--- a/src/BioHelpers_FABER/rmsd.py
+++ b/src/BioHelpers_FABER/rmsd.py
@@ -102,7 +102,7 @@ def rmsd_from_rot_tran(
     """Calculate an RMSD like value for a given set of vectors x and y with a given rotation matrix and translation vector
     Mathematical formula:
 
-    .. math:: \mathrm{RMSD} = \frac{1}{M} \sum_{k=1..M} |\mathfrak{U}\mathbf{x} + \mathbf{r} - \mathbf{y}|^2
+    .. math:: \mathrm{RMSD} = \\frac{1}{M} \sum_{k=1..M} |\mathfrak{U}\mathbf{x} + \mathbf{r} - \mathbf{y}|^2
 
     **Important Note:** The translation vector differs from Kabsch algorithm, there you translate befor rotating. In Coutsias paper it is the otherway round.