import of references

Hello Mendeley Until now I have used RefWorks, but my library in Copenhagen, Denmark, stops using RefWorks at the end of 2016, so I have tried to export all my references from Refworks to Mendeley. For most of the references the export was sucsesfull, bul for one of my databases, called oldenborrerDK, only 1457 of the 1567 references was exported - I tried to export the references in different ways, but with but same result. Why??? How van I find the missing references??? Hope you can help me! Best wishes Kjeld Christensen