Nielsen, E. MPI for Aeronomy, Max Planck Institute for Solar System Research, Max Planck Society; Department Planets and Comets, Max Planck Institute for Solar System Research, Max Planck Society;
Marvlag, E., Scourfield, M. W. J., Walker, A. D. M., Sutcliefe, P. R., & Nielsen, E. (1991). Simultaneous observations of omega band related phenomena in both hemispheres. Journal of Atmospheric and Terrestrial Physics, 53, 309-317.