To cite package ‘optimflex’ in publications use:

  Cho E (2026). _optimflex: Derivative-Based Optimization with
  User-Defined Convergence Criteria_. R package version 0.1.7,
  <https://github.com/eunscho/optimflex>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {optimflex: Derivative-Based Optimization with User-Defined Convergence
Criteria},
    author = {Eunseong Cho},
    year = {2026},
    note = {R package version 0.1.7},
    url = {https://github.com/eunscho/optimflex},
  }