References of imported pdfs are missing


I have the problem that of some pdfs the reference field remains blank although pdfs are available. Now I cannot quote properly and still could not find the cause of the absence of only few articles. Is there anything I can do about it or any specific reason why of some articles the reference information is not imported? Or should I simply enter reference details manually?

Thanks a lot for any help!



If you are importing PDFs directly or from a folder, to create records, the PDF must contain metadata, or EndNote can’t extract the various information into fields.  What is the source of the PDFs?