@online{
   timsrc,
   author = "Flegel, Heinrich",
   title = "Herausforderung Umwelt",
   publisher = "Universität Tübingen",
   year = "2002",
   month = "Jan",
   day = "22",
   url = "https://timms.uni-tuebingen.de:443/tp/UT_20020122_001_umwelt_0001",
   urldate = "2024-05-18"
}