To cite the MASS package in publications use:
Venables WN, Ripley BD (2002).Modern Applied Statistics with S, Fourth edition.Springer, New York.ISBN 0-387-95457-0,https://www.stats.ox.ac.uk/pub/MASS4/.
Corresponding BibTeX entry:
@Book{, title = {Modern Applied Statistics with S}, author = {W. N. Venables and B. D. Ripley}, publisher = {Springer}, edition = {Fourth}, address = {New York}, year = {2002}, note = {ISBN 0-387-95457-0}, url = {https://www.stats.ox.ac.uk/pub/MASS4/}, }