{{cite journal | last1=Khan | first1=Q. U. | author2=T.H. Flower | author3=Sanaullah | year=2013 | title=INFLUENCE OF SOIL PHOSPHORUS ON ENZYME ACTIVITY, RYEGRASS YIELD AND EXTRACTABLE PHOSPHATE | journal=Journal of Animal and Plant Sciences | volume=23 | issue=1 | pages=222-226 | issn=1018-7081 | eissn=2309-8694 | publisher=Pakistan Agricultural Scientists Forum | url=https://thejaps.org.pk/AbstractView.aspx?mid=2013-JAPS-134}}