To cite sparr in publications use:

T. M. Davies, J. C. Marshall, M. L. Hazelton (2017). Tutorial on kernel estimation of continuous spatial and spatiotemporal relative risk; Statistics in Medicine, [in press].

Corresponding BibTeX entry:

  @Article{,
    title = {Tutorial on kernel estimation of continuous spatial and
      spatiotemporal relative risk},
    author = {T. M. Davies and J. C. Marshall and M. L. Hazelton},
    journal = {Statistics in Medicine},
    year = {2017},
    pages = {[in press]},
  }