@book{Laack1999,
  author    = {Laack, Walter van},
  title     = {Der Schl{\"u}ssel zur Ewigkeit},
  publisher = {van Laack},
  address   = {Aachen},
  isbn      = {978-3-9805239-4-3},
  pages     = {285 S.},
  year      = {1999},
  language  = {de}
}