To cite package 'ModelMap' in publications use:

  Freeman, Elizabeth and Frescino, Tracey (2009). ModelMap: Modeling
  and Map production using Random Forest and Stochastic Gradient
  Boosting. USDA Forest Service, Rocky Mountain Research Station, 4919
  S 1500 W, Suite 200, Riverdale, UT 84405, USA.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {ModelMap: Modeling and Map Production using Random Forest and Related Stochastic Models},
    author = {Elizabeth Freeman and Tracey Frescino},
    year = {2018},
    organization = {USDA Forest Service, Rocky Mountain Research Station},
    address = {507 25th street, Ogden, UT, USA},
    note = {elizabeth.a.freeman@usda.gov},
  }
