@book{Haeckel2006,
  author    = {Ernst Haeckel},
  title     = {Berg- und Seefahrten ; [1857 - 1883]},
  url       = {http://caliban.mpiz-koeln.mpg.de/~stueber/haeckel/berg_und_see/index.html},
  year      = {2006},
}