Siami, Koroush, Yaghoubi, Saeed Reza, Faramarzi, Ali, Javadi, Mohammad. Effect of redroot pigweed (Amaranthus retroflexus L.) in various densities and emergence times on yield and yield components of sunflower (Helianthus annus L.). Agroecology Journal. 2008;4(3):49-61. doi: