@electronic{www.flightradar24.com,
   title       = {Flightradar24.com - Live flight tracker!}, 
   url         = {http://www.flightradar24.com/},
   biburl      = {https://puma.uni-kassel.de/url/70267f68e3aa6474ce288651545b8250/stumme},
   keywords    = {airplane everyaware flight flug fluglärm flugzeuge lärm maps noise pollution traffic travel visualization},
   added-at    = {2013-03-20T18:09:53.000+0100},
   description = {},
   interhash   = {70267f68e3aa6474ce288651545b8250}, 
   intrahash   = {70267f68e3aa6474ce288651545b8250}
}

@electronic{www.dfld.de,
   title       = {Deutscher Fluglärmdienst e.V. (DFLD)}, 
   url         = {http://www.dfld.de/},
   biburl      = {https://puma.uni-kassel.de/url/de85905efd4b61559d4df4c51686c680/stumme},
   keywords    = {deutscher dfld everyaware fluglärm fluglärmdienst flugzeug lärm noise plane planes pollution},
   added-at    = {2013-03-20T18:08:16.000+0100},
   description = {},
   interhash   = {de85905efd4b61559d4df4c51686c680}, 
   intrahash   = {de85905efd4b61559d4df4c51686c680}
}