Denise Elizabeth McKinney Treadwell, D. D., McKinney, D. E., & Creamer, N. G. (2003). From philosophy to science: A brief history of organic horticulture in the United States. HortScience, 38(5), 1009–1014. Frampton, J., & McKinney, D. (2002). The North Carolina Premium Fraser Fir Seed Cooperative. Limbs & Needles, 29(2), 10–13.