diff --git a/python/hccd/path_tracker.py b/python/hccd/path_tracker.py
index 957e386..0af85b6 100644
--- a/python/hccd/path_tracker.py
+++ b/python/hccd/path_tracker.py
@@ -15,7 +15,7 @@ class PathTracker:
     References:
       [1] T. Chen and T.-Y. Li, “Homotopy continuation method for solving
           systems of nonlinear and polynomial equations,” Communications in
-          Information and Systems, vol. 15, no. 2, pp. 119–307, 2015
+          Information and Systems, vol. 15, no. 2, pp. 119-307, 2015
     """
 
     def __init__(self, Homotopy, euler_step_size=0.05, euler_max_tries=10, newton_max_iter=5,