@inbook{400221,
     title = {II. Gedanken in Betreff einer k\"unftig aufzustellenden Theorie der geraden Linie},
     booktitle = {Bernard Bolzano's Schriften},
     series = {GDML\_Books},
     publisher = {Kr\'alovsk\'a \v cesk\'a spole\v cnost nauk v Praze},
     address = {Praha},
     year = {1948},
     pages = {37-48},
     url = {http://dml.mathdoc.fr/item/400221}
}