Spahni, R., J. Chappellaz, T.F. Stocker, L. Loulergue, G. Hausammann, K. Kawamura,
J. Flückiger, J. Schwander, D. Raynaud, V. Masson-Delmotte, and J. Jouzel. 2005.
Atmospheric methane and nitrous oxide of the late Pleistocene from Antarctic ice cores.
Science 310, 1317-1321, 2005.