To cite EQUIL2 in publications use:

Werness P, Brown C, Smith L, Finlayson B (1985). “Equil2: A Basic Computer Program for the Calculation of Urinary Saturation.” Journal of Urology, 134(6), 1242–1244. ISSN 0022-5347, 1527-3792. doi:10.1016/S0022-5347(17)47703-2. https://www.jurology.com/doi/10.1016/S0022-5347%2817%2947703-2.

Corresponding BibTeX entry:

  @Article{,
    title = {{Equil2: {A} {Basic} {Computer} {Program} for the
      {Calculation} of {Urinary} {Saturation}}},
    volume = {{134}},
    issn = {{0022-5347, 1527-3792}},
    shorttitle = {{Equil2}},
    url =
      {https://www.jurology.com/doi/10.1016/S0022-5347%2817%2947703-2},
    doi = {10.1016/S0022-5347(17)47703-2},
    abstract = {A BASIC computer program for the calculation of urinary
      supersaturation with respect to the common kidney stone
      components is described. In vitro and in vivo tests show that the
      program described accurately calculates supersaturation. The
      application of this computer program to urolithiasis research is
      discussed.},
    language = {en},
    number = {6},
    urldate = {2021-11-06},
    journal = {Journal of Urology},
    author = {Peter G. Werness and Charles M. Brown and Lynwood H.
      Smith and Birdwell Finlayson},
    month = {Dec},
    year = {1985},
    pages = {1242--1244},
  }