00273    a2200097   4500020001500000082001800015245005900033260004000092300001500132650002800147  a0335142761  a004.0151bOPE  aChapter 7 logic and languagebBlock III (Chapters 7-9)  aWaltonbOpen Universityc1988g1988  a55p.c29cm  aMathematical principles