AL-Dawdi , Ali H., et al. “PERFORMANCE OF THREE MAIZE HYBRIDS (Zea Mays L.) TO PLANT DENSITY AND NITROGEN FERTILIZER”. Diyala Agricultural Sciences Journal , vol. 7, no. 1, June 2015, pp. 133-47, https://journal.djas.uodiyala.edu.iq/index.php/dasj/article/view/1564.