@book{BallmannCollinsDelalandeetal.2015,
  author    = {Peter Ballmann and Rodney Collins and G{\´e}rard Delalande and Alain Mishellany and Jaques P. van den Elshout and Roger Sym},
  title     = {Pr{\"u}fen von Gesteinsk{\"o}rnungen f{\"u}r das Bauwesen},
  year      = {2015},
}