00305pam a2200121 a 4500020000500000041000800005082001700013100001400030245008500044250001000129260003100139300001300170  c  aeng  a005.131bMIS  amishara .  aTheary Of Computer scince Automata, Languages and ComputationhTextual Documents  a2007.  aNew Delhi :bPHI Learning.  a422 pg .