To cite Distance in publications use:

Miller DL, Rexstad E, Thomas L, Marshall L, Laake JL (2019). “Distance Sampling in R.” Journal of Statistical Software, 89(1), 1–28. doi:10.18637/jss.v089.i01.

Corresponding BibTeX entry:

  @Article{,
    title = {Distance Sampling in {R}},
    author = {David L. Miller and Eric Rexstad and Len Thomas and Laura
      Marshall and Jeffrey L. Laake},
    journal = {Journal of Statistical Software},
    year = {2019},
    volume = {89},
    number = {1},
    pages = {1--28},
    doi = {10.18637/jss.v089.i01},
  }