@inbook{402686,
     title = {P\v redmluva},
     booktitle = {Po\v cet differenci\'aln\'\i },
     series = {GDML\_Books},
     publisher = {Jednota \v ceskoslovensk\'ych mathematik\r u a fysik\r u},
     address = {Praha},
     year = {1923},
     pages = {V-VII},
     url = {http://dml.mathdoc.fr/item/402686}
}