Edberg, N. J. T., Brain, D. A., Lester, M., Cowley, S. W. H., Modolo, R., Fränz, M., et al. (2009). Plasma boundary variability at Mars as observed by Mars Global Surveyor and Mars Express. Annales Geophysicae, 27(9), 3537-3550. doi:10.5194/angeo-27-3537-2009.