Conference Paper
Wiegelmann, T.; Solanki, S. K.: Why are coronal holes indistinguishable from the quiet sun in transition region radiation? In: Proc. SOHO 15 `Coronal Heating', pp. 35 - 40 (Eds. Walsh, R. W.; Ireland, J.; Danesy, D.; Fleck, B.). ESA Publ. Div., Noordwijk (2004)