ingested iwslt 2016 (#1833)

* ingested iwslt 2016

Author: davidstap

bin/anthology/papers.py

@@ -47,7 +47,7 @@ def __init__(self, paper_id, ingest_date, volume, formatter=None, venue_index=No
         self.venue_index = venue_index
         self._id = paper_id
         self._ingest_date = ingest_date
-        self._bibkey = False
+        self._bibkey = None
         self._citeproc_json = None
         self.is_volume = paper_id == "0"