Fellegi, Ivan P. & Alan B. Sunter (1969) "A Theory of Record Linkage," Journal of the American Statistical Association, 64, pp. 1183-1210 in Wendy Alvey & Beth Kilss (eds.) Record Linkage Techniques — 1985, Department of the Treasury Internal Revenue Service Statistics of Income Division, December 1985, Pub. 1299 (2-86), pp. 51-78. [ Link to working paper no. 1367 section 1]