@book{WestrichSchwenningerHerrmannetal.2009,
  author    = {Paul Westrich and Hans Richard Schwenninger and Mike Herrmann and Martin Klatt and Matthias Klemm and Rainer Prosi and Arno Schanowski},
  title     = {Rote Liste der Bienen Baden-W{\"u}rttembergs},
  year      = {2009}
}