text Puebla, Pue.] [s.e.] [1980] 1980 monographic 16 h. ; anexo fotocopia24-76 Ponencia presentada en : International seminar on Training and Evaluation Agricultural Programmes of Development in Traditional Agricultural Zones (1980 : Puebla, Pue.) Nigeria Condiciones rurales 67448 971013 20220329141407.0