prepared jointly by the Government of Liberia (Liberian Cartographic Service) and the Government of the United Kingdom (Directorate of Overseas Surveys)Government of the United Kingdom (Directorate of Overseas Surveys) for the Government of Liberia (Liberian Cartographic Service)1983-1986<YG1-L3-5.0>
prepared by the U.S. Geological Survey and the Liberian Geological Survey under the joint sponsorship of the government of Liberia and the Agency for International Development, U.S. Department of StateU. S. Geological Survey in cooperation with the Liberian Geological Survey1972-1973<YG1-L3-25.0>