Wilhelm, K. MPI for Aeronomy, Max Planck Institute for Solar System Research, Max Planck Society; Department Sun and Heliosphere, Max Planck Institute for Solar System Research, Max Planck Society;
Maltby, P., Brynildsen, N., Fredvik, T., Kjeldseth-Moe, O., & Wilhelm, K. (2000). On the sunspot transition region. Solar Physics, 190, 429-450.