Mycorrhizae in sustainable agriculture : proceedings of a symposium sponsosred by divisions S-3 and S-4 of the soil science of America, division A-8 of the American society of agronomy, and division C-2 of the crop science of America in Denver, Co. 31 Oct. 1991 - Bethlenfalvay, G.J., ed.; Linderman, R.G. (American Society of Agronomy Madison, 1992)