diff --git a/piscat/Preproccessing/filtering.py b/piscat/Preproccessing/filtering.py
index 6494768..cb6bc87 100644
--- a/piscat/Preproccessing/filtering.py
+++ b/piscat/Preproccessing/filtering.py
@@ -217,10 +217,14 @@ def __init__(self, inter_flag_parallel_active=True):
 
         References
         ----------
+        The Radial Variance Transform code has been adopted from the GitHub repository mentioned below.
+
         [1] Kashkanova, Anna D., et al. "Precision single-particle localization
         using radial variance transform." Optics Express 29.7 (2021):
         11070-11083.
 
+        [2] https://github.com/SandoghdarLab/rvt
+
         """
         self.cpu = CPUConfigurations()
         self._kernels_fft_cache = {}