To cite TractoR (of which 'tractor.base' is part) in publications, please use:

Jonathan D. Clayden, Susana Muñoz Maniega, Amos J. Storkey, Martin D. King, Mark E. Bastin, Chris A. Clark (2011). TractoR: Magnetic resonance imaging and tractography with R. Journal of Statistical Software 44(8):1-18. URL http://www.jstatsoft.org/v44/i08/.

Corresponding BibTeX entry:

  @Article{,
    title = {{TractoR}: Magnetic resonance imaging and tractography
      with {R}},
    author = {Jonathan D. Clayden and Susana Mu\~{n}oz Maniega and Amos
      J. Storkey and Martin D. King and Mark E. Bastin and Chris A.
      Clark},
    journal = {Journal of Statistical Software},
    year = {2011},
    volume = {44},
    number = {8},
    pages = {1--18},
    url = {http://www.jstatsoft.org/v44/i08/},
  }