To cite rtorf in publications use at least the first, if not both:

Schuldt, et al. Multi-laboratory compilation of atmospheric methane data for the period 1983-2021.NOAA - Global Monitoring Laboratory, 10.25925/20230301, https://gml.noaa.gov/ccgg/obspack/citation.php, 2014.

Ibarra-Espinosa S (2026). rtorf: Observations, Footprints and Receptors ('rtorf') and HYSPLIT Configuration Tools. R package version 4.3.2, https://github.com/ibarraespinosa/rtorf.

Thanks

Corresponding BibTeX entries:

  @Article{,
    title = {Multi-laboratory compilation of atmospheric methane data
      for the period 1983-2021},
    journal = {NOAA - Global Monitoring Laboratory},
    author = {Kenneth N. Schuldt and John Mund and Tuula Aalto and
      James B. Abshire and Ken Aikin and Grant Allen and Arlyn Andrews
      and Francesco Apadula and Sabrina Arnold and Bianca Baier and
      Peter Bakwin and Jakub Bartyzel and Gilles Bentz and Peter
      Bergamaschi and Andreas Beyersdorf and Tobias Biermann and
      Sebastien C. Biraud and Pierre-Eric Blanc and Harald Boenisch and
      David Bowling and Gordon Brailsford and Willi A. Brand and
      Dominik Brunner and Thao P. Bui and Lukas Bäni and Francescopiero
      Calzolari and Cecilia S. Chang and Huilin Chen and Gao Chen and
      Lukasz Chmura and Shane Clark and Sites Climadat and Aurelie
      Colomb and Roisin Commane and Lino Condori and Franz Conen and
      Sébastien Conil and Cédric Couret and Paolo Cristofanelli and
      Emilio Cuevas and Roger Curcoll and Bruce Daube and Kenneth J.
      Davis and Martine {De Mazière} and Stephan {De Wekker} and
      Jonathan M. Dean-Day and Julian Della Coletta and Marc Delmotte
      and Tatiana Di Iorio and Elizabeth DiGangi and Joshua P. DiGangi
      and Russell Dickerson and James W. Elkins and Michael Elsasser
      and Lukas Emmenegger and Shuangxi Fang and Marc L. Fischer and
      Grant Forster and James France and Arnoud Frumau and Marta
      Fuente-Lastra and Michal Galkowski and Luciana V. Gatti and
      Torsten Gehrlein and Christoph Gerbig and Francois Gheusi and
      Emanuel Gloor and Daisuke Goto and Tim Griffis and Samuel Hammer
      and Thomas F. Hanisco and Chad Hanson and László Haszpra and Juha
      Hatakka and Martin Heimann and Michal Heliasz and Daniela Heltai
      and Stephan Henne and Arjan Hensen and Christian Hermans and Ove
      Hermansen and Eric Hintsa and Antje Hoheisel and Jutta Holst and
      Laura T. Iraci and Viktor Ivakhov and Daniel A. Jaffe and Armin
      Jordan and Warren Joubert and Hui-Yun Kang and Anna Karion and
      Stephan R. Kawa and Victor Kazan and Ralph F. Keeling and Petri
      Keronen and Jooil Kim and Jörg Klausen and Tobias Kneuer and
      Mi-Young Ko and Pasi Kolari and Katerina Kominkova and Eric Kort
      and Elena Kozlova and Paul B. Krummel and Dagmar Kubistin and
      Susan S. Kulawik and Nicolas Kumps and Casper Labuschagne and
      David H. Lam and Xin Lan and Ray L. Langenfelds and Andrea Lanza
      and Olivier Laurent and Tuomas Laurila and Thomas Lauvaux and
      Jost Lavric and Beverly E. Law and Choong-Hoon Lee and Haeyoung
      Lee and John Lee and Irene Lehner and Kari Lehtinen and Reimo
      Leppert and Ari Leskinen and Markus Leuenberger and W.H. Leung
      and Ingeborg Levin and Janne Levula and John Lin and Matthias
      Lindauer and Anders Lindroth and Zoe M. Loh and Morgan Lopez and
      Chris R. Lunder and Mikaell O. Löfvenius and Toshinobu Machida
      and Ivan Mammarella and Giovanni Manca and Andrew Manning and
      Alistair Manning and Michal V. Marek and Per Marklund and Josette
      E. Marrero and Damien Martin and Melissa Y. Martin and Giordane
      A. Martins and Hidekazu Matsueda and Kathryn McKain and Harro
      Meijer and Frank Meinhardt and Lynne Merchant and Jean-Marc
      Metzger and N. Mihalopoulos and Natasha L. Miles and Charles E.
      Miller and John B. Miller and Logan Mitchell and Vanessa Monteiro
      and Stephen Montzka and Fred Moore and Heiko Moossen and Eric
      Morgan and Josep-Anton Morgui and Shinji Morimoto and J. W.
      Munger and David Munro and Mathew Mutuku and Cathrine L. Myhre
      and Meelis Mölder and Jennifer Müller-Williams and Shin-Ichiro
      Nakaoka and Jaroslaw Necki and Sally Newman and Sylvia Nichol and
      Euan Nisbet and Yosuke Niwa and David M. Njiru and Steffen M. Noe
      and Yukihiro Nojiri and Simon O'Doherty and Florian Obersteiner
      and Bill Paplawsky and Caroline L. Parworth and Jeff Peischl and
      Olli Peltola and Wouter Peters and Carole Philippon and Salvatore
      Piacentino and Jean M. Pichon and Penelope Pickers and Steve
      Piper and Joseph Pitt and Christian Plass-Dülmer and Stephen M.
      Platt and Steve Prinzivalli and Michel Ramonet and Ramon Ramos
      and Xinrong Ren and Enrique Reyes-Sanchez and Scott J. Richardson
      and Louis-Jeremy Rigouleau and Haris Riris and Pedro P. Rivas and
      Michael Rothe and Yves-Alain Roulet and Thomas Ryerson and Ju-Mee
      Ryoo and Maryann Sargent and Motoki Sasakawa and Bert Scheeren
      and Martina Schmidt and Tanja Schuck and Marcus Schumacher and
      Jennifer Seibel and Thomas Seifert and Mahesh K. Sha and Paul
      Shepson and Michael Shook and Christopher D. Sloop and Paul D.
      Smith and Gerard Spain and Jason M. St. Clair and David Steger
      and Martin Steinbacher and Britton Stephens and Colm Sweeney and
      Lise L. Sørensen and Risto Taipale and Shinya Takatsuji and
      Pieter Tans and Kirk Thoning and Helder Timas and Margaret Torn
      and Pamela Trisolino and Jocelyn Turnbull and Alex Vermeulen and
      Brian Viner and Gabriela Vitkova and Stephen Walker and Andrew
      Watson and Ray Weiss and Dietmar Weyrauch and Steven C. Wofsy and
      Justin Worsey and Doug Worthy and Irène Xueref-Remy and Emma L.
      Yates and Dickon Young and Camille Yver-Kwok and Sönke Zaehle and
      Andreas Zahn and Christoph Zellweger and Miroslaw Zimnoch and
      Rodrigo A. {de Souza} and Alcide G. di Sarra and Danielle {van
      Dinther} and Pim {van den Bulk}},
    year = {2024},
    url = {https://gml.noaa.gov/ccgg/obspack/citation.php},
    doi = {10.25925/20230301},
  }
  @Manual{,
    title = {rtorf: Observations, Footprints and Receptors ('rtorf')
      and HYSPLIT Configuration Tools},
    author = {Sergio Ibarra-Espinosa},
    year = {2026},
    note = {R package version 4.3.2},
    url = {https://github.com/ibarraespinosa/rtorf},
  }