Format of trimmed author list for BibTeX export

[CastleStar14654]

Currently, if one set the max number of authors of BibTeX exportation, the format would be "xxx, xxx, xxx, and et al.", which is literally wrong, because "et al." means "and others" already. Most BibTeX style would understand it as an additional author with the name of "et al." It would be better to change the format to "xxx, xxx, xxx, and others".

The related code is the following line:

export_service/exportsrv/formatter/bibTexFormat.py

Line 227 in 430a20f

return author_list + " and et al."