@online{ timsrc, author = "Werner, Klaus AND Nagel, Thorsten", title = "Vorlesung Einführung in die Astronomie I, 7. Stunde", publisher = "Universität Tübingen", year = "2008", month = "Nov", day = "26", url = "https://timms.uni-tuebingen.de:443/tp/UT_20081126_001_astro1_0001", urldate = "2024-12-21" }