To cite package ‘proActiv’ in publications use:

  Demircioglu, Deniz, et al. A Pan-cancer Transcriptome Analysis
  Reveals Pervasive Regulation through Alternative Promoters Cell 178.6
  (2019): 1465-1477

A BibTeX entry for LaTeX users is

  @Article{,
    title = {A Pan-cancer Transcriptome Analysis Reveals Pervasive Regulation through Alternative Promoters},
    author = {Deniz Demircioglu and Engin Cukuroglu and Martin Kindermans and Tannistha Nandi and Claudia Calabrese and Nuno A. Fonseca and Andre Kahles and Kjong-Van Lehmann and Oliver Stegle and Alvis Brazma and Angela N. Brooks and Gunnar Ratsch and Patrick Tan and Jonathan Goke},
    year = {2019},
    journal = {Cell},
    doi = {10.1016/j.cell.2019.08.018},
    volume = {178},
    issue = {6},
    pages = {1465},
  }