Thongsamut, W., N. Udomprasert, and T. Pornprom. “Effects of Plant Spacing on Light Interception, Growth and Yield of Sunflower (Helianthus annuus L.) ”. Thai Agricultural Research Journal, vol. 28, no. 2, Aug. 2010, p. 187, doi:10.14456/thaidoa-agres.2010.7.