Doerr, Hans-Peter Department Sun and Heliosphere, Max Planck Institute for Solar System Research, Max Planck Society;
Löhner-Böttcher, J., Schmidt, W., Schlichenmaier, R., Doerr, H.-P., Steinmetz, T., & Holzwarth, R. (2018). Absolute velocity measurements in sunspot umbrae. Astronomy and Astrophysics, 617: A19. doi:10.1051/0004-6361/201832886.