To cite 'basicspace' in publications use:

Carroll R, Hare C, Lewis JB, Lo J, Poole KT, Rosenthal H (2016). “Recovering a Basic Space from Issue Scales in R.” Journal of Statistical Software, 69(7), 1–21. doi:10.18637/jss.v069.i07.

Corresponding BibTeX entry:

  @Article{,
    entry = {Article},
    title = {Recovering a Basic Space from Issue Scales in {R}},
    author = {Royce Carroll and Christopher Hare and Jeffrey B. Lewis
      and James Lo and Keith T. Poole and Howard Rosenthal},
    journal = {Journal of Statistical Software},
    year = {2016},
    volume = {69},
    number = {7},
    pages = {1--21},
    doi = {10.18637/jss.v069.i07},
  }