TY JOUR TI Effects of regional integration on trade in agricultural products in ECOWAS KW agriculture integration KW regional integration KW agriculture trade KW ECOWAS KW common external tariff KW gravity model KW zero trade KW agricultural policies JO Theoretical economics AU N’Goran, K.C. AU Titova, L.A. PY 2025 IS 0 PB Yaroslavl State Technical University