00273    a2200097   4500020001500000082001800015245005900033260004000092300001500132650002800147  a0335142710  a004.0151bOPE  aChapter 2 describing functionsbBlock I (Chapters 1-3)  aWaltonbOpen Universityc1988g1988  a41p.c29cm  aMathematical principles