na INLIS000000000010771 20210520151129 210520||||||||| | ||| |||| || | 0 521 34437 9 010-0521010771 en 63/ROL/e 63/ROL/e ROLING, Niels Extension science : Information systems in agricultural development Cambridge Cambridge University 1988 xii, 233 p.: ill.; 24 cm. AGRICULTURE -- EXTENSION 320/ODA/1990