1. Wood, G. L., 1930:—The Pacific Basin, Oxford Clarendon Press.
2. Blumenstock, D. I., and C. W. Thornthwaite, 1951:—Yearbook of Agriculture, U.S.D.A., Washington, p. 98–127.
3. Rhoad, A. C., 1941:—Yearbook of Agriculture, U.S.D.A., Washington, p. 513.