@inbook{403896, title = {4. kapitola. Je\v st\v e p\v etadvacet \'uloh}, booktitle = {Princip matematick\'e indukce}, series = {GDML\_Books}, publisher = {Mlad\'a fronta}, address = {Praha}, year = {1977}, pages = {69-113}, url = {http://dml.mathdoc.fr/item/403896} }
(éd.). 4. kapitola. Ještě pětadvacet úloh, dans Princip matematické indukce, GDML_Books, (1977), pp. 69-113. http://gdmltest.u-ga.fr/item/403896/