To cite BB in publications use:

Ravi Varadhan, Paul Gilbert (2009). BB: An R Package for Solving a Large System of Nonlinear Equations and for Optimizing a High-Dimensional Nonlinear Objective Function. Journal of Statistical Software, 32(4), 1-26. URL http://www.jstatsoft.org/v32/i04/.

Corresponding BibTeX entry:

  @Article{,
    title = {{BB}: An {R} Package for Solving a Large System of
      Nonlinear Equations and for Optimizing a High-Dimensional
      Nonlinear Objective Function},
    author = {Ravi Varadhan and Paul Gilbert},
    journal = {Journal of Statistical Software},
    year = {2009},
    volume = {32},
    number = {4},
    pages = {1--26},
    url = {http://www.jstatsoft.org/v32/i04/},
  }