diff --git a/1-enrich-with-datacite/concatenate-enrich-dois.py b/1-enrich-with-datacite/concatenate-enrich-dois.py
index c5e2c5f3c04ef56d5f3218fafcb2e29fc1a38b7b..b1c7657f49c24438ccc46a72668a99377bf3d489 100644
--- a/1-enrich-with-datacite/concatenate-enrich-dois.py
+++ b/1-enrich-with-datacite/concatenate-enrich-dois.py
@@ -56,14 +56,23 @@ for doi in dois : #[:300]
 ## if new datasets has been founded
 if temp_rows :
 	df_fresh = pd.DataFrame(temp_rows)
-
+	i_to_drop = []
+	dois_added = list(df_old["doi"])
+	to_del = []
 	for i in range(0, len(df_fresh)):
 		result = my_functions.get_origin_version(df_fresh.loc[df_fresh.index[i], "doi"])
-		if result[0] is in df_old["doi"]: df_fresh.drop(df_fresh.index[i])
-		else:
+		if result[0] not in dois_added: 
+			dois_added.append(result[0])
 			df_fresh.loc[df_fresh.index[i], "doi"] = result[0]
 			df_fresh.loc[df_fresh.index[i], "relation_nbInstances"] = result[1]
 			df_fresh.loc[df_fresh.index[i], "relation_nbCitation"] = result[2]
+		else:
+			to_del.append(i)
+			
+	df_fresh.drop(to_del, inplace=True)
+	print("Nombre de dois supprimés : " + str(len(to_del)))
+	
+	print("Nb dois a garder : " + str(len(dois_added)))
 
 	df_concat = pd.concat([df_old, df_fresh], ignore_index=True)