* [https://agresearchmag.ars.usda.gov/2002/jun/rubber Wood, Marcia. June 2007. Sunflower Rubber? Agricultural Research. USDA.] | * [https://agresearchmag.ars.usda.gov/2002/jun/rubber Wood, Marcia. June 2007. Sunflower Rubber? Agricultural Research. USDA.] |