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;
Shen, C. S., & Nielsen, E. (1987). The spatial component of ionospheric electron flow derived from two-dimensional drift measurements. Journal Geophysical Research, 92, 305.