To cite package 'regress' in publications use:

David Clifford, Peter McCullagh (2014). The regress package R package version 1.3-15.

David Clifford, Peter McCullagh (2006), The regress function, R News 6:2, 6-10

Corresponding BibTeX entries:

  @Manual{,
    title = {The regress package},
    author = {David Clifford and Peter McCullagh},
    year = {2014},
    note = {R package version 1.3-15},
  }

  @Article{,
    title = {The regress function},
    author = {David Clifford and Peter McCullagh},
    journal = {R News},
    year = {2006},
    volume = {6},
    number = {2},
    pages = {6},
    pages = {10},
    month = {May},
  }