To cite npbr in publications use:
Abdelaati Daouia, Thibault Laurent, Hohsuk Noh (2017). npbr: A Package for Nonparametric Boundary Regression in R. Journal of Statistical Software, 79(9), 1-43.<doi:10.18637/jss.v079.i09>
Corresponding BibTeX entry:
@Article{, title = {{npbr}: A Package for Nonparametric Boundary Regression in {R}}, author = {Abdelaati Daouia and Thibault Laurent and Hohsuk Noh}, journal = {Journal of Statistical Software}, year = {2017}, volume = {79}, number = {9}, pages = {1--43}, doi = {10.18637/jss.v079.i09}, }