diff --git a/README.md b/README.md
index 9c8e11d..0669a24 100644
--- a/README.md
+++ b/README.md
@@ -28,3 +28,4 @@ See the following script for instructions:
     
     Isaiah Norton, Walid Ibn Essayed, Fan Zhang, Sonia Pujol, Alex Yarmarkovich, Alexandra J. Golby, Gordon Kindlmann, Demian Wassermann, Raul San Jose Estepar, Yogesh Rathi, Steve Pieper, Ron Kikinis, Hans J. Johnson, Carl-Fredrik Westin and Lauren J. O'Donnell. 
     SlicerDMRI: Open Source Diffusion MRI Software for Brain Cancer Research. Cancer Research 77(21), e101-e103, 2017.
+
diff --git a/src/tract_feat.py b/src/tract_feat.py
index e8dd35d..50b0a9d 100644
--- a/src/tract_feat.py
+++ b/src/tract_feat.py
@@ -463,7 +463,7 @@ def bilateralize_feature_OLD(y_names, y_data, x_data, fliped_copy=False):
 	
 	# Replace y label of right structure to its corresponding left structure
 	# Note: here we assume that right structure is next to the left structure
-	y_data_bilateral_ = y_data
+	y_data_bilateral_ = np.copy(y_data)
 	for y_label in all_y_labels:
 		if 'left' in y_names[y_label]:
 			# print y_label, y_names[y_label], y_names[y_label+1]
@@ -480,7 +480,7 @@ def bilateralize_feature_OLD(y_names, y_data, x_data, fliped_copy=False):
 	y_names_bilateral = np.array(y_names_bilateral)
 	
 	# Make bilateral x data
-	x_data_reflected = x_data
+	x_data_reflected = np.copy(x_data)
 	x_data_reflected[:,:,:,0] = -x_data_reflected[:,:,:,0]
 
 	x_data_bilateral = np.concatenate((x_data, x_data_reflected), axis=2)
@@ -649,7 +649,7 @@ def bilateralize_feature(y_data, y_names, y_validation=None, verbose=False):
 
 def bilateral_X_data(x_data, fliped_copy=False, y_data=None):
 
-	x_data_reflected = x_data
+	x_data_reflected = np.copy(x_data)
 	x_data_reflected[:,:,:,0] = -x_data_reflected[:,:,:,0]
 
 	if x_data_reflected.shape[-1] == 4: