Keller, H. J. (1993). Who is who in service to the earth: People, projects, organizations, key words ; over 8000 listings and cross-indexes of people, projects, and organizations, dedicated to a sustainable future (2. ed.). Saur.
Chicago-Zitierstil (17. Ausg.)Keller, Hans J. Who Is Who in Service to the Earth: People, Projects, Organizations, Key Words ; over 8000 Listings and Cross-indexes of People, Projects, and Organizations, Dedicated to a Sustainable Future. 2. ed. München ; London ; New York ; Paris: Saur, 1993.
MLA-Zitierstil (9. Ausg.)Keller, Hans J. Who Is Who in Service to the Earth: People, Projects, Organizations, Key Words ; over 8000 Listings and Cross-indexes of People, Projects, and Organizations, Dedicated to a Sustainable Future. 2. ed. Saur, 1993.