1989 - Rivers at Risk Concerned Citizen's Guide to Hydropower (Paperback) → Hardcover ISBN-13: 9780933280823 ISBN-10: 0933280823 Genres: Science & Math, Engineering & Transportation, Outdoors & Nature ? 1989 - Rivers at Risk Concerned Citizen's Guide to Hydropower (Hardcover) → Paperback ISBN-13: 9780933280830 ISBN-10: 0933280831 Genres: Business & Money, Science & Math ? |