Which citation style is the most concise and has the least impact on word count? I'm writing a research proposal with a small maximum word count. References are included in this word count. Fortunately, the citation style is not specified. 

I was wondering if there is any (widely accepted) citation style that will generally produce the shortest citations. As far as I've found, MLA seems to be the shortest as it switches author names to "et al." when there's four or more authors, whereas other citation styles that I've looked at only switch with a higher number of authors. Is there any style that would consistently produce shorter citations?
Coming back to this question when writing a grant with very strict word limit, I discovered that the most concise citation AND bibliography style must be the Science (without titles).
Example:


  1.R. Hisakata, S. Nishida, A. Johnston, Curr. Biol. 26, 1911–1915 (2016).


You can find the citation-style-language csl file in the official csl styles github repository, that you can download and use in Zotero, Mendeley, RefWorks, etc.
If you're an EndNote person, see the style file in the most popular answer to this ResearchGate question