To cite osmdata in publications use:

Mark Padgham, Bob Rudis, Robin Lovelace, Maëlle Salmon (2017). “osmdata.” Journal of Open Source Software, 2(14), 305. doi:10.21105/joss.00305, https://joss.theoj.org/papers/10.21105/joss.00305.

Corresponding BibTeX entry:

  @Article{,
    title = {osmdata},
    author = {{Mark Padgham} and {Bob Rudis} and {Robin Lovelace} and
      {Maëlle Salmon}},
    journal = {Journal of Open Source Software},
    year = {2017},
    volume = {2},
    number = {14},
    pages = {305},
    month = {jun},
    publisher = {The Open Journal},
    url = {https://joss.theoj.org/papers/10.21105/joss.00305},
    doi = {10.21105/joss.00305},
  }