To cite package ‘ecb’ in publications use:

  Persson E (2023). _ecb: Programmatic Access to the European Central
  Bank's Statistical Data Warehouse_. R package version 0.4.2,
  <https://CRAN.R-project.org/package=ecb>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {ecb: Programmatic Access to the European Central Bank's Statistical
Data Warehouse},
    author = {Eric Persson},
    year = {2023},
    note = {R package version 0.4.2},
    url = {https://CRAN.R-project.org/package=ecb},
  }