@online{
   timsrc,
   author = "Santangelo, Andrea",
   title = "X-ray Astronomy - A note on history, a look into the future",
   publisher = "Universität Tübingen",
   year = "2013",
   month = "Sep",
   day = "26",
   url = "https://timms.uni-tuebingen.de:443/tp/UT_20130926_001_AG2013_0001",
   urldate = "2024-05-03"
}