To cite package 'HH' in publications use:

Richard M. Heiberger (2016). HH: Statistical Analysis and Data Display: Heiberger and Holland. R package version 3.1-31. URL http://CRAN.R-project.org/package=HH

To cite the HH book (first edition) in publications use:

Richard M. Heiberger and Burt Holland (2004). Statistical Analysis and Data Display: An Intermediate Course with Examples in S-Plus, R, and SAS. Springer-Verlag, New York. URL http://www.springer.com/us/book/9781441923202

To cite the HH book (second edition) in publications use:

Richard M. Heiberger and Burt Holland (2015). Statistical Analysis and Data Display: An Intermediate Course with Examples in R. Springer-Verlag, New York. URL http://www.springer.com/us/book/9781493921218

To cite likert from HH in publications use:

Richard M. Heiberger, Naomi B. Robbins (2014). Design of Diverging Stacked Bar Charts for Likert Scales and Other Applications. Journal of Statistical Software, 57(5), 1-32. URL http://www.jstatsoft.org/v57/i05/.

Corresponding BibTeX entries:

@Manual{, title = {HH: Statistical Analysis and Data Display: Heiberger and Holland.}, author = {Richard M. Heiberger}, year = {2016}, note = {R package version 3.1-31}, url = {http://CRAN.R-project.org/package=HH}, }

@Book{, title = {Statistical Analysis and Data Display: An Intermediate Course with Examples in {S-Plus}, {R}, and {SAS}}, author = {Richard M. Heiberger and Burt Holland}, year = {2004}, publisher = {Springer-Verlag, New York}, edition = {First}, url = {http://www.springer.com/us/book/9781441923202}, }

@Book{, title = {Statistical Analysis and Data Display: An Intermediate Course with Examples in {R}}, author = {Richard M. Heiberger and Burt Holland}, year = {2015}, publisher = {Springer-Verlag, New York}, edition = {Second}, url = {http://www.springer.com/us/book/9781493921218}, }

@Article{, title = {Design of Diverging Stacked Bar Charts for Likert Scales and Other Applications}, author = {Richard M. Heiberger and Naomi B. Robbins}, journal = {Journal of Statistical Software}, year = {2014}, volume = {57}, number = {5}, pages = {1--32}, url = {http://www.jstatsoft.org/v57/i05/}, }