To cite in publications use:
Terry Therneau and Thomas Lumley and Kjetil Halvorsen and Kurt Hornik (2018). date: Functions for handling dates. R package version 1.2-38.
Corresponding BibTeX entry:
@Manual{, title = {date: Functions for handling dates}, author = {Terry Therneau and Thomas Lumley and Kjetil Halvorsen and Kurt Hornik}, year = {2018}, note = {R package version 1.2-38. S original by Terry Therneau, R port by Thomas Lumley, Kjetil Halvorsen, and Kurt Hornik.}, url = {https://CRAN.R-project.org/package=date}, }