00278nam a2200109Ia 450000500170000000800410001708200120005810000170007024500300008726000430011730000080016020260224040835.0260224s9999||||xx |||||||||||||| ||und|| a633 DIX aDixit, R.S.  0aCropping system research. aLudhiana : Kalyani Publications c2007 a194