@inbook{400184,
title = {20. Bolzano an Exner},
booktitle = {Bernard Bolzano's Schriften},
series = {GDML\_Books},
publisher = {Kr\'alovsk\'a \v cesk\'a spole\v cnost nauk},
address = {Praha},
year = {1935},
pages = {104-106},
url = {http://dml.mathdoc.fr/item/400184}
}
Bolzano, Bernard. 20. Bolzano an Exner, dans Bernard Bolzano's Schriften, GDML_Books, (1935), pp. 104-106. http://gdmltest.u-ga.fr/item/400184/