@online{ timsrc, author = "Werner, Klaus", title = "Vorlesung Einführung in die Astronomie I, 6. Stunde", publisher = "Universität Tübingen", year = "2008", month = "Nov", day = "19", url = "https://timms.uni-tuebingen.de:443/tp/UT_20081119_001_astro1_0001", urldate = "2024-11-21" }