@online{ timsrc, author = "Werner, Klaus", title = "Vorlesung Einführung in die Astronomie I, 15. Stunde", publisher = "Universität Tübingen", year = "2009", month = "Feb", day = "04", url = "https://timms.uni-tuebingen.de:443/tp/UT_20090204_001_astro1_0001", urldate = "2024-12-21" }