{{cite journal | last1=Shahzad | first1=K. | author2=A. Khan | author3=J. Smith | author4=M. Saeed | author5=S.A. Khan | year=2015 | title=RESPONSE OF MAIZE TO DIFFERENT NITROGEN SOURCES AND TILLAGE SYSTEMS UNDER HUMID SUBTROPICAL CONDITIONS | journal=Journal of Animal and Plant Sciences | volume=25 | issue=1 | pages=189-197 | issn=1018-7081 | eissn=2309-8694 | publisher=Pakistan Agricultural Scientists Forum | url=https://thejaps.org.pk/AbstractView.aspx?mid=2015-JAPS-27}}