This book was originally published as a doctoral thesis and was de fended by the author at the Tilburg School of Economics in 1969. It has the characteristics of a work on industrial econometrics. On the one hand relevant economical, statistical and mathematical theory is treated and on the other a model for a very actual situation has been created and utilised to solve a practical problem. The selection from current reference material always has a personal tinge of course, and other theoreticians will find some of the author's departures from the theme a little unnecessary. However, if the...