@article {38073,
	title = {Regeneration challenges. In : S. Navratil and P. B. Chapman, editors, Aspen management for the 21st century. Proceedings of a symposium held November 20-21, 1990, Edmonton, Alberta},
	year = {1991},
	pages = {15-38},
	institution = {Canadian Forest Service, Northern Forest Research Centre and Poplar Council of Canada},
	author = {Navratil, S.}
}
