EDIT

Done. Still needs to be tested.

The markers were imported

I checked the final import result and it looks ok.

SELECT r.id, r.uuid, r.titleCache, m.flag, mt.titleCache, mt.id
FROM Reference r INNER JOIN Reference_Marker MN ON MN.Reference_id = r.id INNER JOIN Marker m ON m.id = MN.markers_id
INNER JOIN DefinedTermBase mt ON mt.id = m.markerType_id
WHERE mt.id = 965 
;
SELECT DISTINCT osb.citation_id
-- SELECT deb.id, MN.*, osb.id, feature.id, osb.citation_id, osb.sourceType
FROM DescriptionElementBase deb INNER JOIN DescriptionElementBase_OriginalSourceBase MN ON MN.DescriptionElementBase_id = deb.id
INNER JOIN OriginalSourceBase osb ON osb.id = MN.sources_id
INNER JOIN DefinedTermBase feature ON deb.feature_id =  feature.id
WHERE feature.id = 991 AND osb.sourceType <> 'DIM'