qualité de l'eau (2) récréation (2) projet (2) méthodologie (2) infrastructure (2) information (2) effet (2) ville (2) Money (2) Control (2) Article (2) Illustrations (2) Methodology (2) Illustrations (2) Contingent valuation (2) Water quality (2) Wages (2) Recreation (2) Persons (2) Money (2) Methodology (2) Human beings (2) Grammar, Comparative and general--Article (2) Confidence (2) Article (2) Willingness to pay (2) Recreation (2)