@inbook{400166,
     title = {Vorwort des Herausgebers},
     booktitle = {Bernard Bolzano's Schriften},
     series = {GDML\_Books},
     publisher = {Kr\'alovsk\'a \v cesk\'a spole\v cnost nauk v Praze},
     address = {Praha},
     year = {1931},
     pages = {1-2},
     url = {http://dml.mathdoc.fr/item/400166}
}