http://en.wikiquote.org/wiki/Ludwig_von_Mises

1949 von Mises Human Action

Part Four: Catallactics or Economics of the Market Society,

Chapter XX: Interest, Credit Expansion, The Trade Cycle,

§ 8: The Monetary or Circulation Theory of the Trade Cycle

p 570

...the recurrence of periods of boom which are followed by periods of depression, is the unavoidable outcome of the attempts, repeated again and again, to lower the gross market rate of interest by means of credit expansion. There is no means of avoiding the final collapse of a boom brought about by credit expansion. The alternative is only whether the crisis should come sooner as the result of voluntary abandonment of further credit expansion, or later as a final and total catastrophe of the currency system involved.