{{cite journal | last1=Szczepanek | first1=M. | author2=E. Wilczewski | year=2016 | title=MAIZE RESPONSE TO SOIL-APPLIED HUMIC SUBSTANCES AND FOLIAR FERTILIZATION WITH POTASSIUM | journal=Journal of Animal and Plant Sciences | volume=26 | issue=5 | pages=1298-1303 | issn=1018-7081 | eissn=2309-8694 | publisher=Pakistan Agricultural Scientists Forum | url=https://thejaps.org.pk/AbstractView.aspx?mid=2016-JAPS-170}}