To cite package ‘kirby21.fmri’ in publications use:

  Landman BA, Huang AJ, Gifford A, Vikram DS, Lim IAL, Farrell JA,
  Bogovic JA, Hua J, Chen M, Jarso S, others (2011). “Multi-parametric
  neuroimaging reproducibility: a 3-T resource study.” _Neuroimage_,
  *54*(4), 2854-2866. <https://www.nitrc.org/projects/multimodal/>.

A BibTeX entry for LaTeX users is

  @Article{landman2011multi,
    title = {Multi-parametric neuroimaging reproducibility: a 3-T resource study},
    author = {Bennett A Landman and Alan J Huang and Aliya Gifford and Deepti S Vikram and Issel Anne L Lim and Jonathan AD Farrell and John A Bogovic and Jun Hua and Min Chen and Samson Jarso and others},
    journal = {Neuroimage},
    volume = {54},
    number = {4},
    pages = {2854--2866},
    year = {2011},
    url = {https://www.nitrc.org/projects/multimodal/},
    publisher = {Elsevier},
  }