To cite package 'msa' in publications use:

Obermeier WA, Lehnert LW, Kammann CI, Müller C, Grünhage L, Luterbacher J, Erbs M, Moser G, Seibert R, Yuan N, Bendix J (under review). “Reduced CO2 fertilization in temperate C3 grasslands under more extreme weather conditions.” Nature Climate Change.

Corresponding BibTeX entry:

  @Article{,
    title = {Reduced CO2 fertilization in temperate C3 grasslands under
      more extreme weather conditions},
    author = {W. A. Obermeier and L. W. Lehnert and C. I. Kammann and
      C. M\"{u}ller and L. Gr\"{u}nhage and J. Luterbacher and M. Erbs
      and G. Moser and R. Seibert and N. Yuan and J. Bendix},
    year = {under review},
    journal = {Nature Climate Change},
  }