To cite palmtree in publications use:

  Seibold H, Hothorn T, Zeileis A (2019). “Generalised Linear Model
  Trees with Global Additive Effects.” _Advances in Data Analysis and
  Classification_, *13*(3), 703-725. doi:10.1007/s11634-018-0342-1
  <https://doi.org/10.1007/s11634-018-0342-1>.

A BibTeX entry for LaTeX users is

  @Article{,
    title = {Generalised Linear Model Trees with Global Additive Effects},
    author = {Heidi Seibold and Torsten Hothorn and Achim Zeileis},
    journal = {Advances in Data Analysis and Classification},
    year = {2019},
    volume = {13},
    number = {3},
    pages = {703--725},
    doi = {10.1007/s11634-018-0342-1},
  }