@online{ timsrc, author = "Werner, Klaus", title = "Vorlesung Einführung in die Astronomie I, 13. Stunde", publisher = "Universität Tübingen", year = "2009", month = "Jan", day = "21", url = "https://timms.uni-tuebingen.de:443/tp/UT_20090121_001_astro1_0001", urldate = "2024-11-24" }