@article{HaertnagelSchaalSchmidt1989,
  author    = {R. H{\"a}rtnagel and W. Schaal and Thomas Schmidt},
  title     = {Erdgasspeicherung in Xanten. Anlage zur unterirdischen Speicherung von Erdgas in Kavernen.},
  journal   = {Bergbau},
  volume    = {40},
  number    = {8},
  pages     = {392 -- 397},
  year      = {1989},
}