To cite the alr4 package in publications use:

Weisberg S (2014). Applied Linear Regression, Fourth edition. Wiley, Hoboken NJ. http://z.umn.edu/alr4ed.

Corresponding BibTeX entry:

  @Book{,
    title = {Applied Linear Regression},
    edition = {Fourth},
    author = {Sanford Weisberg},
    year = {2014},
    publisher = {Wiley},
    address = {Hoboken {NJ}},
    url = {http://z.umn.edu/alr4ed},
  }