To cite tufterhandout in publications use:
Sachs MC (2015). tufterhandout: Tufte-style html document format for rmarkdown. R package version 1.2.1, http://sachsmc.github.io/tufterhandout.
Corresponding BibTeX entry:
@Manual{, title = {tufterhandout: Tufte-style html document format for rmarkdown}, author = {Michael C. Sachs}, year = {2015}, note = {R package version 1.2.1}, url = {http://sachsmc.github.io/tufterhandout}, }