@book{frankfurt+a+m+bad+nauheim+giessen+wetzlar+siegen+hagen+witten+essen,
    author = {Perker, Waldemar},
    title = {Frankfurt a. M. - Bad Nauheim - Gießen - Wetzlar - Siegen - Hagen - Witten - Essen},
    address = {Frankfurt a. M.},
    publisher = {Expedition von Hendschels Telegraph, M. Hendschel},
    date = {1913}
}