To cite package rtop in publications use:

Skoien JO, Bloschl G, Laaha G, Pebesma E, Parajka J, Viglione A (2014). “Rtop: An R package for interpolation of data with a variable spatial support, with an example from river networks.” Computers & Geosciences.

Corresponding BibTeX entry:

  @Article{,
    title = {Rtop: An R package for interpolation of data with a
      variable spatial support, with an example from river networks},
    author = {J. O. Skoien and G. Bloschl and G. Laaha and E. Pebesma
      and J. Parajka and A. Viglione},
    journal = {Computers & Geosciences},
    year = {2014},
  }