stringr, plotrix, pwr, testthat, openintro
stringr, plotrix, pwr, testthat, openintro, httr, whisker,
yaml
stringr, testthat, httr, yaml, RCurl, digest
stringr, testthat, httr, yaml, RCurl, digest, tools
stringr, testthat, httr (>= 1.1.0), yaml, RCurl, digest,
tools, utils, methods
stringr, testthat (>= 1.0.2), httr (>= 1.1.0), yaml, RCurl,
digest, tools, methods