@online{ timsrc, author = "Werner, Klaus AND Nagel, Thorsten", title = "Vorlesung Einführung in die Astronomie I, 2. Stunde", publisher = "Universität Tübingen", year = "2008", month = "Oct", day = "22", url = "https://timms.uni-tuebingen.de:443/tp/UT_20081022_001_astro1_0001", urldate = "2024-11-21" }