14.1 problem 1
  14.2 problem 2
  14.3 problem 3
  14.4 problem 4
  14.5 problem 5
  14.6 problem 6
  14.7 problem 7
  14.8 problem 8
  14.9 problem 9
  14.10 problem 10
  14.11 problem 11
  14.12 problem 12
  14.13 problem 13
  14.14 problem 14
  14.15 problem 15
  14.16 problem 16
  14.17 problem 17
  14.18 problem 18
  14.19 problem 19
  14.20 problem 20
  14.21 problem 21
  14.22 problem 22
  14.23 problem 23
  14.24 problem 24
  14.25 problem 25
  14.26 problem 27
  14.27 problem 29