reference appears twice in the bibliography

parrenin

In a LO document I wrote, I referred 4 times to exactly the same reference in my zotero database.
However, the reference appears twice in the bibliography (and formatted in a slightly different way).
I can provide the document if needed (apparently it is not possible to attach a document to the forum)

fbennett

If open each item for editing, you will find an "Open in ..." link at the bottom. If you use that to open each item, I think you'll find that at least one of them differs from the others.

parrenin

No, I really have only one of such references.
Again, I can provide the .odt file and my zotero database if needed.
Why is there no attachment facility on this forum?

adamsmith

yeah, that's pretty much impossible. Somehow there are two references to the same item. Did you do what fbennett suggested and follow the "Open in" link?

DWL-SDCA

@parrenin
You can "attach" documents and screen-shots by uploading them to any of the many free holding places available on the web and including the link within your forum post. (EDIT: pastebin, imageshack, dropbox, etc.)

Regarding your main problem:

"...formatted in a slightly different way" is a strong indicatation that carefully following fbennett's advice will identify the problem. Closely examine each for slight differences.

Check your library for duplicates. The utility will identify potential duplicates even if the records have slight differences.

If the references are in a document that was made using a group library and group effort it may be possible that a group member inserted the problem reference.

EDIT: See https://forums.zotero.org/discussion/29655

Similar to the group issue, could _you_ have slightly different versions of the refence if you are working from more than one computer?