Export Item... and Create Bibliography From Item... do not generate equivalent BibTeX
Example (both have been reformatted with emacs bibtex-mode M-x bibtex-reformat)
First Export -> Bibtex
@article{tollestrup_congressional_2012,
title = {The Congressional appropriations process: An introduction},
volume = 23,
url =
{https://www.wisconsin.edu/government-relations/download/The-Congressional-Appropriations-Process-An-Introduction.pdf},
shorttitle = {The Congressional appropriations process},
pages = {R42388},
journaltitle = {Congressional Research Service, February},
author = {Tollestrup, Jessica},
urldate = {2017-10-02},
date = 2012,
file = {The Congressional Appropriations Process\: An
Introduction:/Users/gla/Zotero/storage/WTA94DRM/The
Congressional Appropriations Process An
Introduction.pdf:application/pdf}
}
Second Create -> Bibtex
@article{Tollestrup_2012,
title = {The Congressional appropriations process: An introduction},
volume = 23,
url =
{https://www.wisconsin.edu/government-relations/download/The-Congressional-Appropriations-Process-An-Introduction.pdf},
journal = {Congressional Research Service, February},
author = {Tollestrup, Jessica},
year = 2012,
pages = {R42388}
}
Several fields are missing for the latter. It is often more convenient to "Create" a bibliography and then paste the bibtex into a file for specific references, rather than "Export" a file and merge the new exports into the existing .bib. It seems like both commands should produce the same output.
First Export -> Bibtex
@article{tollestrup_congressional_2012,
title = {The Congressional appropriations process: An introduction},
volume = 23,
url =
{https://www.wisconsin.edu/government-relations/download/The-Congressional-Appropriations-Process-An-Introduction.pdf},
shorttitle = {The Congressional appropriations process},
pages = {R42388},
journaltitle = {Congressional Research Service, February},
author = {Tollestrup, Jessica},
urldate = {2017-10-02},
date = 2012,
file = {The Congressional Appropriations Process\: An
Introduction:/Users/gla/Zotero/storage/WTA94DRM/The
Congressional Appropriations Process An
Introduction.pdf:application/pdf}
}
Second Create -> Bibtex
@article{Tollestrup_2012,
title = {The Congressional appropriations process: An introduction},
volume = 23,
url =
{https://www.wisconsin.edu/government-relations/download/The-Congressional-Appropriations-Process-An-Introduction.pdf},
journal = {Congressional Research Service, February},
author = {Tollestrup, Jessica},
year = 2012,
pages = {R42388}
}
Several fields are missing for the latter. It is often more convenient to "Create" a bibliography and then paste the bibtex into a file for specific references, rather than "Export" a file and merge the new exports into the existing .bib. It seems like both commands should produce the same output.
However: you should be able to select the export style for "quick copy" and copy/paste using that instead. It won't handle citekey collisions, but will get you everything else you're interested in.