Beck, B. F. (1989). Engineering and environmental impacts of sinkholes and karst: Proceedings of the Third Multidisciplinary Conference on Sinkholes and the Engineering and Environmental Impacts of Karst, St. Petersburg Beach, Florida, 2-4 October 1989. Rotterdam: A. A. Balkema.
Παραπομπή Chicago StyleBeck, Barry F. Engineering and Environmental Impacts of Sinkholes and Karst: Proceedings of the Third Multidisciplinary Conference On Sinkholes and the Engineering and Environmental Impacts of Karst, St. Petersburg Beach, Florida, 2-4 October 1989. Rotterdam: A. A. Balkema, 1989.
Παραπομπή MLABeck, Barry F. Engineering and Environmental Impacts of Sinkholes and Karst: Proceedings of the Third Multidisciplinary Conference On Sinkholes and the Engineering and Environmental Impacts of Karst, St. Petersburg Beach, Florida, 2-4 October 1989. Rotterdam: A. A. Balkema, 1989.