Hadisaputro, Suyoto, 		Rochiman, Kusriningrum, 		PDN, Mirzawan, 		Sukarso, Gunawan, AND 		Sugiharto, Bambang.
" The Roles of Nitrogen and Potassium to Phosphoenolpyruvate Carboxylase Activity in the Leaves of Ratoon Crop M 442-51 and PS 60 Sugarcane Varieties" <em>Jurnal ILMU DASAR</em> [Online], Volume 9 Number 1 (1 January 2008)