To cite skylight in publications use:

Hufkens, Koen, Meier, M. C, Evens, Ruben, Paredes, Arán J, Karaardiç, Hakan, Vercauteren, Stef, Van Gysel, Ann, Fox, W. J, Pacheco, Miguel C, Silva d, P. L, Fernandes, Sandra, Henriques, Pedro, Elias, Gonçalo, Costa, T. L, Poot, Martin, Kearsley, Lyndon (2023). “Evaluating the effects of moonlight on the vertical flight profiles of three western palaearctic swifts.” Proceedings of the Royal Society B: Biological Sciences, 290(2010), 20230957. doi:10.1098/rspb.2023.0957.

Corresponding BibTeX entry:

    author = {{Hufkens} and {Koen} and {Meier} and Christoph M. and
      {Evens} and {Ruben} and {Paredes} and Josefa Arán and {Karaardiç}
      and {Hakan} and {Vercauteren} and {Stef} and {Van Gysel} and
      {Ann} and {Fox} and James W. and {Pacheco} and Carlos Miguel and
      da Silva and Luis P. and {Fernandes} and {Sandra} and {Henriques}
      and {Pedro} and {Elias} and {Gonçalo} and {Costa} and Luís T. and
      {Poot} and {Martin} and {Kearsley} and {Lyndon}},
    title = {Evaluating the effects of moonlight on the vertical flight
      profiles of three western palaearctic swifts},
    journal = {Proceedings of the Royal Society B: Biological
    volume = {290},
    number = {2010},
    pages = {20230957},
    year = {2023},
    doi = {10.1098/rspb.2023.0957},
    abstract = { Recent studies have suggested the presence of
      moonlight mediated behaviour in avian aerial insectivores, such
      as swifts. Here, we use the combined analysis of state-of-the-art
      activity logger data across three swift species, the common,
      pallid and alpine swifts, to quantify flight height and activity
      in responses to moonlight-driven crepuscular and nocturnal light
      conditions. Our results show a significant response in flight
      heights to moonlight illuminance for common and pallid swifts,
      i.e. when moon illuminance increased flight height also
      increased, while a moonlight-driven response is absent in alpine
      swifts. We show a weak relationship between night-time
      illuminance-driven responses and twilight ascending behaviour,
      suggesting a decoupling of both crepuscular and night-time
      behaviour. We suggest that swifts optimize their flight behaviour
      to adapt to favourable night-time light conditions, driven by
      light-responsive and size-dependent vertical insect
      stratification and weather conditions. },