M.A. Clark H.R. Compson J.D. Devine William C. Evans A.M. Humphrey G.W. Kling E.J. Koenigsberg J. P. Lockwood G.N. Wagner M. L. Tuttle 1987 application/pdf 10.3133/ofr8797 en U.S. Geological Survey, The 21 August 1986 Lake Nyos gas disaster, Cameroon; final report of the United States scientific team to the Office of U.S. Foreign Disaster Assistance of the Agency for International Development reports