@PhdThesis{phdFockel,
  author =   {Markus Fockel},
  title =    {Safety requirements engineering for early {SIL} tailoring},
  school =   {Universit\"at Paderborn},
  year =   2018,
  month =    Dec,
 url = {https://www.bodden.de/pubs/phdFockel.pdf},
}