Convert RIS or NBIB or JSON to bibtex?

To convert from RIS to BibTeX, I use this as part of a shell script:

ris2xml <filename>.ris | xml2bib -b > <filename>.bib

RIS is therefore my second choice of download format and quite handy since several places don't provide BibTeX but do provide RIS export.

Both ris2xml and xml2bib are provided by bibutils.

If you use a GNU/Linux distro, check for a package before resorting to a direct CTAN download as that will be easier to maintain in most cases.

For Arch Linux, there's a PKGBUILD in AUR, for example, and I think Fedora provides a package, as well.

You sure about that?

@article{garcia2003genome,
  title={The genome sequence of Yersinia pestis bacteriophage $\varphi$A1122 reveals an intimate history with the coliphage T3 and T7 genomes},
  author={Garcia, Emilio and Elliott, Jeffrey M and Ramanculov, Erlan and Chain, Patrick SG and Chu, May C and Molineux, Ian J},
  journal={Journal of bacteriology},
  volume={185},
  number={17},
  pages={5248--5262},
  year={2003},
  publisher={Am Soc Microbiol}
}

Tool doi2bib has moto "give us a DOI and we will do our best to get you the BibTeX entry" and it works for DOI specified in given json.