chapter
Acknowledgements
Pages 1

Reprinted from Economica (November 195 7), pp. 324-42, by permission.

2 Reprinted from Oxford Economic Papers, NS, vol. 14 (October 1962), pp. 205-17 , by permission. © Oxford University Press.

3 Reprinted from Oxford Economic Papers, NS, vol. 17 (July 1965), pp. 2 I9-36 , by permission. © Oxford University Press.