R markdown citation identifiers

问题

R markdown allows specifying a bibliography file using the bibliography metadata field in a YAML metadata section. For example:

---
title: "Sample Document"
output: html_document
bibliography: bibliography.bib
---

The bibliography may have multiple formats in addition to BibTeX, such as RIS, EndNote, XML, ISI, MEDLINE, and others.

The problem is that all usage examples use BibTeX. For example:

@article{ahu61,
   author={Arrow, Kenneth J. and Leonid Hurwicz and Hirofumi Uzawa},
   title={Constraint qualifications in maximization problems},
   journal={Naval Research Logistics Quarterly},
   volume={8},
   year=1961,
   pages={175-191}
}

To cite the article above, you can use:

Blah blah [@ahu61]

That assumes that the entry has an identifier. How do I use citations for other formats that do not have identifiers?

For example, MEDLINE has clear element/field descriptions and ID is not one of them. Using article identifier (AID) or adding an additional ID field does not work.

来源：https://stackoverflow.com/questions/43825541/r-markdown-citation-identifiers