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2. Munz, P. A. and Keck, D. D. (1973) A California Flora (with Supplement by P. A. Munz). University of California Press, Berkeley, California.
3. Madson, B. A. (1951) Winter Covercrops. Circular 174, California Agricultural Extension Service, College of Agriculture, University of California, June 1951.
4. Johnny’s selected seeds (1983) Green Manures – A Mini Manual. Johnny’s selected seeds, Albion, Maine 04910.
5. Verhallen, A., Hayes, A. and Taylor, T. (2003) Cover crops – Oats, Ministry of Agriculture, Food and Rural Affairs, Ontario, Canada.