Quick update to my reference managers roundup to add CiteAs:

CiteAs is a simple tool for getting a properly-formatted citation for any DOI or – more importantly – open source software. Here’s an example for the stringr R package. The URLs for CiteAs are nicely formatted (http://citeas.org/cite/https://cran.r-project.org/web/packages/stringr for the stringr example), making it easy to create a “Cite this page” bookmarklet.