Willingness-to-pay and demand for sanitation products in rural northern Ghana: Impacts of seasonality and methodology. - Trimmer, John; Kisiangani, Joyce; Odame-Boafo, Bessy Ewoenam; Sam, Stanley Bortse; Poulin, Chloé; Osei, Dominic; Bauza, Valerie (PLoS Water, 2025)