To cite opendataes in publications use:

  Cimentada, J. and Jorge Lopez (2019). Interact with the datos.gob.es
  API to download public data from all of Spain R package version 0.0.1

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {Interact with the datos.gob.es API to download public data from all of Spain},
    author = {Jorge Cimentada and Jorge Lopez},
    year = {2019},
    note = {R package version 0.0.1},
    url = {https://github.com/ropenspain/opendataes, https://ropenspain.github.io/opendataes/},
  }