na INLIS000000000002273 20240424062655 0010-0424000019 ta 240424 f 0 eng 630 630 VAL a Valera, Jaime B. An Introduction To Extension Delivery Systems Manila : Island Publishing House, 1987 186 hlm. ; 21 cm. Pengairan Vicente A. Martinez Ramiro F. Plopino 202031001.04.0011