diff --git a/1-enrich-with-datacite/z_personal_functions.py b/1-enrich-with-datacite/z_personal_functions.py
index a0d8932139f682a1eedcc99570d424a760fc3363..91dd2a77ce5c79dfc8fe5058d98a5bc01ea488ce 100644
--- a/1-enrich-with-datacite/z_personal_functions.py
+++ b/1-enrich-with-datacite/z_personal_functions.py
@@ -1,5 +1,20 @@
 import requests, json
 
+def get_origin_version(doi):
+    req = requests.get( f"https://api.datacite.org/dois/{doi}" )
+    res = req.json()
+    try:
+        origins = res["data"]["attributes"]["relatedIdentifiers"]
+    except:
+        return doi
+    else:
+        if origins == []: return doi
+        for i in origins:
+            if i["relationType"] != "IsVersionOf":
+                return doi
+            else:
+                return get_origin_version(i["relatedIdentifier"])
+
 def get_md_from_datacite( doi ) : 
     """
 	retrieve data research metadata from datacite