@article {19300,
	title = {Positive Feedback Investment Strategies and Destabilizing Rational Speculation},
	journal = {Journal of Finance},
	volume = {45},
	number = {2},
	year = {1990},
	pages = {379-395},
	author = {J.Bradford DeLong and Andrei Shleifer and Lawrence H. Summers and Robert J. Waldmann}
}
