@inbook{403007,
     title = {P\v redmluva},
     booktitle = {O sou\v radnic\'\i ch v rovin\v e},
     series = {GDML\_Books},
     publisher = {Jednota \v cesk\'ych matematik\r u a fysik\r u},
     address = {Praha},
     year = {1942},
     pages = {3-4},
     url = {http://dml.mathdoc.fr/item/403007}
}