diff --git a/toardb/timeseries/crud.py b/toardb/timeseries/crud.py
index 91a6c08029ec2b34614124337fefe0726320adbb..e55274f4cd554b3c3ecc6efbe4d4f0e833d88ff4 100644
--- a/toardb/timeseries/crud.py
+++ b/toardb/timeseries/crud.py
@@ -60,8 +60,13 @@ def get_timeseries(db: Session, timeseries_id: int, fields: str = None):
                 pass
     return db_object
 
-
-def get_citation(db: Session, timeseries_id: int, datetime: dt.datetime = dt.datetime.now(dt.timezone.utc)):
+# https://www.reddit.com/r/flask/comments/ypqk40/default_datetimenow_not_using_current_time/
+# dt.datetime.now(dt.timezone.utc) cannot be used as default value, since it will already be
+# evaluated at the start of the worker process and **not** when actually accessing the data
+# def get_citation(db: Session, timeseries_id: int, datetime: dt.datetime = dt.datetime.now(dt.timezone.utc)):
+def get_citation(db: Session, timeseries_id: int, datetime: dt.datetime = None):
+    if not datetime:
+        datetime = dt.datetime.now(dt.timezone.utc)
     db_object = db.query(models.Timeseries).filter(models.Timeseries.id == timeseries_id).first()
     # there is a mismatch with additional_metadata
     PI = "unknown"
@@ -91,7 +96,7 @@ def get_citation(db: Session, timeseries_id: int, datetime: dt.datetime = dt.dat
         station = get_stationmeta_by_id(db, station_id=db_object.station_id).name
         dataset_version = db_object.provider_version
     citation = f"{PI}: time series of {var} at {station}, accessed from the TOAR database on {datetime}"
-    if list_of_data_originators:
+    if attribution and list_of_data_originators:
         attribution = attribution.format(list_of_data_originators=list_of_data_originators)
     if dataset_version != 'N/A':
         citation += f", original dataset version {dataset_version}"
diff --git a/toardb/timeseries/timeseries.py b/toardb/timeseries/timeseries.py
index 0987515699a916c4a07d3ed2a403c50afff60162..c821b17816f44950719155e170e75be2dc00b2c6 100644
--- a/toardb/timeseries/timeseries.py
+++ b/toardb/timeseries/timeseries.py
@@ -54,7 +54,7 @@ def get_timeseries2(timeseries_id: int, db: Session = Depends(get_db)):
 
 #build citation text of one timeseries (known its ID)
 @router.get('/timeseries/citation/{timeseries_id}')
-def get_citation(timeseries_id: int, datetime: dt.datetime = dt.datetime.now(dt.timezone.utc), db: Session = Depends(get_db)):
+def get_citation(timeseries_id: int, datetime: dt.datetime = None, db: Session = Depends(get_db)):
     citation = crud.get_citation(db, timeseries_id=timeseries_id, datetime=datetime)
     return citation