To cite the sft package in publications use:

Houpt, J.W., Blaha, L.M., McIntire, J.P., Havig, P.R. and Townsend, J.T. (2013) Systems Factorial Technology with R. Behavior Research Methods, XX, XX-XX.

Corresponding BibTeX entry:

    title = {Systems Factorial Technology with R},
    author = {Joseph Houpt and Leslie Blaha and John McIntire and Paul
      Havig and James Townsend},
    journal = {Behavior Research Methods},
    pages = {XX-X},
    number = {X},
    volume = {XX},
    year = {2013},