%0 Journal Article %A Calábek, Pavel %T Higher-order differential systems and a regularization operator %J Mathematica Bohemica %D 1999 %P 337-349 %V 124 %N 4 %I mathdoc %U http://geodesic.mathdoc.fr/articles/10.21136/MB.1999.125996/ %R 10.21136/MB.1999.125996 %G en %F 10_21136_MB_1999_125996