@online{
   timsrc,
   author = "Kley, Wilhelm AND Werner, Klaus",
   title = "Streifzug durch die Astronomie, 3. und 4. Stunde",
   publisher = "Universität Tübingen",
   year = "2016",
   month = "Oct",
   day = "25",
   url = "https://timms.uni-tuebingen.de:443/tp/UT_20161025_001_rvastro_0001",
   urldate = "2024-04-19"
}