Dawood, Wisam Malik, et al. “Effect of Row Direction and Plant Distribution on Growth Characteristics of Maize (Zea Mays L . ) ”. Diyala Agricultural Sciences Journal , vol. 1, no. 1, June 2009, pp. 162-71, https://journal.djas.uodiyala.edu.iq/index.php/dasj/article/view/3197.