Systems of frequency curves / William Palin Elderton and Norman Lloyd Johnson. Elderton, William Palin, Sir, 1877-1962. Johnson, Norman Lloyd, joint author. Elderton, William Palin, Sir, 1877-1962. Frequency curves and correlation. Frequency curves. QA273 .E5 1969 519.1 ELS Based on the 4th ed. of Elderton's Frequency curves and correlation. Bibliography: p. 202-205. London, Cambridge U.P., 1969. 1969. 1969 Text viii, 216 p. eng