Smallholder farmers' willingness to pay for multi-stress tolerant varieties: evidence from experimental auctions in Southern Africa. - Ngoma, Hambulo; Mulungu, Kelvin; Pangapanga-Phiri, Innocent; Subakanya, Mitelo; Simutowe, Esau; Setimela, Peter; Chiduwa, Mazvita; Kasoma, Chapwa; Tesfaye, Amsal; Chivasa, Walter (Climate & Development, 2026)