To cite GPIC in publications use:

  Pham, Duy Nghia. 2020. “GPIC: Quantifying Group Performance in
  Individual Competitions.” EdArXiv. June 26.
  doi:10.35542/osf.io/ajz5v.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {GPIC: Quantifying Group Performance in Individual Competitions},
    author = {Duy Nghia Pham},
    publisher = {EdArXiv},
    year = {2020},
    month = {Jun},
    day = {26},
    doi = {10.35542/osf.io/ajz5v},
    url = {https://edarxiv.org/ajz5v/},
  }